Creating Fm capabilities between 2 OSCs

[Addison DS]

Hey everyone,
I know there are some FM capabilities in the native synthesizer group but I want to remake it so it’s more like the famous Serum « Fm from B »
Wich I think is in fact Phase modulation
I want to create 2 independant Osc with a knob activating Phase modulation+amount.
Osc B modulating A.

Just so I have a rough idea on how to try to set it up…
How would you guys would go to create something like that?
I cant really find a intuitive way of doing that but scriptnode is probably the way
Can you help me creating this or at least give some hints of what should I use?

Thanks a lot