Ok i finally got it to work. I redid everything from scratch and now it works somehow. I dont know what exactly made it work this time, but ok i will go through everything step by step (also since theres no tutorial about this, as far as i know).
-So i used faust. I created a new faust file and replaced all variables and stringnames of parameters by non-generic names like "gainer1" or "againer".
-Then i opened hise. Created a new project. From this point on i didnt close or reopen hise whatsoever. When i close hise and reopen the xml it looks like this.

Instead of this, and i dont know why.

So thats why i keep hise open.
-I created a new scriptFX node add the faust dsp file to the correct folder.
-Added the parameter for the gain, and linked it with the cable thingy. And gave all elements and parameter things non-generic names. I did not added a knob to the interface view yet (I think this might be important).
-Then i compiled the dll.

-Checked the box "replace scriptFX modules"
-Added a hardcodedFX node to the FX node (Your script should pop up here)

-Then i removed the scriptFX node.
-I went to the interface designer and added a new knob to the interface view.

-Make sure to select hardcodedMasterFX1 as processorID in the property editor.
-You can add a waveform generator to see if the knob and effect works. (make sure to remove it again).
-Then i exported it as FX plugin

-Now i got the dll in the binaries file and it works.

HiseSnippet 778.3ocuV80aZCCD2FvUC1ezpz164w1opIBzBTsGVW4OqnUnnktp9VkqioXQhcjiS6PS66w93rOR6avlcRnIrh5nnskGfb9ty2Oe2u6bFIEDZXnPBfUNcV.E.eBxYFWMo8DLiC52A.KitR+JUZCNbV.NLj5Bfvhu2nFVtDH94Gu8PrGlSnYKA.mIXD5wLelJa0QG7AlmWOrK8TleNq28f9DAusvSDogRQTUP.lLEeEcH1XVAD3Hb3D.7Un8aX61zc+p0aTu19spQ1kT2dupMpUqoMYrcc6VDJsVyVWBfaz0koDRGEVQC0a5gB2YNSD2vSBvYrP1kdTifMvQG4jkAsmv7bGMOuDB.vRixxRESxRu.Mf4xtc8rr0yiUXk4Q9jFrv8AI6G.jf4fToDHsIxgHYApLMF77XTethJGi00l7PIwV.76n1BsAb0q8wSo8jZgacXqFUqtik9msey3HNQwDbKAenPQOgu01U9RkxU9ZEqeW03wKUmILRgmGUtT0F5f79bbKdj+kT4NVWi8hn2Zn93uXNciUKmRRN04LTv6yYpSBnox8Ddtlbk486VA.ooMSsHEgZSUwUhmkVIb7XtTIf4luIJF94aS.epeGrBOeiz6oNNATohYNNvNzq0sQIk3xnNzvoJQPrs9ABtAAvMVgv9Y.DAOFB.yLu7McXCleZ56Z3yGgktDg9DO.Gpq+8N2V2BJ0ceZg9KrUf6x8zrdgajGVsXqfYHQpBcsbA9mgjwCYpY4Gh7.5Opdu8GqJD2DMhoHSVNFKrDLpqR+KvX5Tkmh5NdLknx.XITuyW2QHUW8QHnj3+xLVfUBMvRGdCNVJ+HOtFRU2HjSyySl+e9jWw+RC.AeTDoX7qFfURlgaOLx2Qe2AgpycbN0KzPyKX5SSjqZjMPvgxciE9o9IUosQFlpzdtx+KwvGSjhKHISPLkkGEuh9byiu4qLZfQ1ZICN70WzbAgr3VcGGqstNVeccb200w8VWGartN1bccr0e1Qy2A7tHkvOYvB.LXT23A8PXWNVyxi6a.+BvUgltC

@Lindon Hi long time ago, i was very busy with university. It compiles for me. Strange that my project was unable to compile for you. For me that was never the problem. For the old project:
It showed the editor of the plugin, but changing the knob value didnt do anything. Your project:
I had to add the knob to the interface, and then i compiled it. But the same thing happened in the daw: it shows the gui but changing the knob value doesnt do anything. In the solution topic this guy says hardcodedFX and ScriptFX should compile the same:
https://forum.hise.audio//post/89792
and since my problem is different than the one of this topic i think theres something else going on...
I dont have any crash or compile problems. Everything shows up, the knob works in HISE, but in the daw the knob doesnt do anything. This is a screenshot from cakewalk, i also tried it in supercollider but it is the same problem.

Are you able to make your project work as a vst plugin?

@Lindon Sorry for the late reply. I do this on the side of my main occupation so i mainly work on this on weekends. Thank you for helping me.

This is the snippet with the scriptFX.

HiseSnippet 1410.3ocuW0saaaCElxIJowqq+LzG.gbkSggmUbZR5BFRyeNynKoFUoA8t.FI5XBSQJHR2X2hc2tX6AXWzaF1SvteWsArWjs2f9FrcHoTrbhgaqw5TPrE44PxOd324iGSFnH7HRzYRNMIgnPHm4ZmJBIRoHE4T9jgIDjyscCFxUc2qKlxQs1G4bG2ivREI0y10tCSvRIIB43L2g5NbVZdj44cauKlg4gjQcgPmJngjukFSUi5s8SdJkwZhiHmPiK38ZOoUnfumfI5C3YN25nDbXO7EjiwZ2J4h9FrrKx4gtOdc+nMhdb8Fq2X0Gu4pgqE1v+Q0We0U2vOrieC+MCIjU2XyyQNKbPDUIRCTXEQBS5thngAcEWxsKvoTI8bFQ2vGE.qrsazdcornqBNRHTMegP0b1P0CbOhFQup+Qgr6YL3MZDECZNklFj7+HfjSAHMuER22MHLklnFYQimOysEGNA6fgylhPw5Kx4Ob2S.NvU0hw8HMSgFWMfJqWudUO3iU1pSednhJ3dB9wBE4Y7JqT9MkWp72U165l5zYh1zKSpfwHoSzrlNjNsAVg2O9bRZUuWgY8IW4Hr8GOltvGVLMztqK3nf2hSUOKgj0tofEoiU52u4I.JKroOKxPH3pxbRbmrSh.FMhjhnvjrn6S4hy8QFvmQ6eRiF+41nWzZerBmOMvLBqRBIUQ0aFm8IuBRhrGvK4tOQ1SIRL9FmH35024tu2Ec.xw04mgUbn9keDdQpFpCIKXb.ESihXj1BIUGxKjU+6PxeR.80FD+lG7qG92u962NtXhOBEiGTTGP1uSG5.SFaGJKVp.L0JFRjQNeg6KjDuHRGbelxS1ClGFk2iDchv3uhLPowjQZIIOV2JxHLY1adMeoOHLjBZB.EUaIyazMSGfDQQTeFVMd1o18LC58ZwTBMumCwfgE2OeDor0mZJ6GJDuuaapJr6jwXoIfQf57o.iYBcet6Ac5PBUi.37tMe4TU0l+Ca4md90jT3JmQCf0WCjwXESRa6GbGoijjR.hC4DQaFdXEINNgQdNf2pdmyDg8zj7aJ9jQB2U6QkvtXNmvjyhF0B+Go6idtnuhxu3HLjWoSqOteb.bkYHYuLzoyvKokmrsqqaq4HAv8+lF+C7jYzW21IynetwQJaniIpKEo8LGGYuCpJ1XuzDjOqy.ezNLl3RshDMiwBmAl9ZKXCS5J3zPcWVOxQ5Nwh9Z4KKbga2OASYZJdPeInAG8Ld.3rojBm4NkjJMS7ht0qA+AT9iEQfoEahCg.6v1XUWctiVVGHpjzZgWQXGCqE4I1ZKFyrdVyqBwF3.TGazYAEJ8QV6b4Gs7bISYT4x0VRqtEjdVxtzsjmpsFhYnSsZ+v9UuJ1fpYSrf10EcAcQoBM1F51vFJkTyZ4lPOeLSG0WCiktFFWxcOFLufZZF.Wv8hbM0h9cWMYqvtOya65gJXPGFxagbt0QT9oEt0y7bDdv056caGT3tFnie4su821NnG4Ra.onmZzjAxhyB7+es891qWtwruSekHFx9LpnnfK0ZrmfSufnjSC8K9oB8GdczadlL5yJNfSLxMxwalkJzJZDcn832PZOM2UH5EiMIyyTMG+uH8DiCSEmEZUS0azaY5AnvbCgeI3Gj.s8FuPJacHPY2mEFN9TciAt5rNvFy5.WaVG3il0At9rNvMl0At46ef5eUTVNnlzBIQsOvPBcbNfigK+LxZHBb+YDTVf8JbMW8pd3jAMgaDLzenzR8uJT+kEI2yR8+RMWuVjLIu9djyO4FQBYvU+d4d6sbtWKuU4biiL.cRghqSUUVVphLSaMF87kWYqxZydesWWooF6JV2q54W0qt8yZ9fWYUM.NdV0y79JuJOrh1wUp5k8xJagP+q47hjt

And this is the hardcodedFX version of it.
HiseSnippet 958.3ocuVsraabCEkTRzoVsMHAnY+.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.eQYu269ie6PzO16DpkN4XfSD7RrvXktKC9Dwqgln7D7ljSDIWY0wY5FEqUN+iuyG0oWivD76AON18wu.eXEWCVtAIqKNdx0pG2UX+TpgyzvUOu2u6q7gdQCzFBDNMJrBcyJPn1WySCo1EaHbpWH.xnKTE5J0TIR634Gk7IzkzbkcI2VHdexERKazxwXokfQHa8eAFKls7kjSCBDL6L.Vgz8UqbPRkam6WcI8BCUH4X4AyJG7J1E.PwgokVnLOFOWXei1bkqf4R2E4xYaL9offe+Pb4+kFFh9AcpUpt7Lp0Hc05mmF0G1ivDPDToDgItx9Rtd1b5lNZWVrOrTLi3ufmBg9NZbgP+IB+ewGQTlQOfkOMwkP9rLNv8VksEbSXcLP6s3XjrmHXoy.Fawi5FF1ZcMr85Z3NqqgOZcMry5Z3tqqg68wMz8eB91TqNJe7BBc1EmlM1GiOUQgp7rNFj.1vwgFp7I4tR6obThq6JCEYsoARWaQI2O4H4dj.ZZh8qcsXayShmrcCg+UBWvBoFg2Ds81ZhVacP0IBmI.XJgUKFassRr7ric6P4vspePUmXuuwaTR1FlZ4p2vyugWy72a6CZUrMATbPiAdO1q1Cq4TrdCuhOpe.B82.ESG71C

@Lindon I assume this was the solution?
https://forum.hise.audio//post/89769
Im still a beginner so im not sure.
I did what the post suggested.
I got this now.

Chorale is the name of the my dsp network that was previously in the script fx node.
And i also replace the knob from the interface with a new knob.

However the problem remains, in my daw, when i turn the knob theres no change in gain.
The post also says something about removing something from the interface.js code, im not sure what is meant with that. Im still a beginner and all the example snippets use scriptfx nodes. I can check the forum but half of the answers i do not really understand because i dont understand the program that well. Could you please help me?

I wrapped some simple faust code with HISE.
Heres the faust code:

declare filename "NJERG.dsp";
declare name "NJERG";
import("stdfaust.lib");
gain = hslider("gain", 1, 0, 1, 0.1);
process = _,_ : (*(gain), *(gain));

I added the parameter to the interface and linked it to the faust parameter:

And when i use a wavegenerator in the master chain:

The turning the knob in the interface preview changes the gain audibly.
So i guess all settings are correct.
So then i remove the wavegenerator from the master chain, so it can take input and work as a FX plugin.
I enable vst3 support and then i export it as a VST plugin.
However when i open it in my DAW turning the gain knob does not change the gain audibly. The default value of the gain is 0.5, and i do hear a drop in audio level when opening the plugin so the audio is passing through and multiplied by 0.5. So is there something wrong i did regarding the interface?

EDIT:
I actually didnt select export as FX plugin but as intstrument, that would maybe explain that the gain knob didnt do anything. However now that re-exported and this time i did select FX plugin, it doesnt even pass through the gain anymore: no gain reduction by default value 0.5 and also changing the knob doesnt do anything.