@s_creator I just do videos. I have one demo video per product.
Very simple videos: https://www.youtube.com/@meatbeatsofficial
I make an audio demo first in Logic, then record the plugin window and use those recordings along with the audio and some background visuals to make a demo video. I try to include enough text in the video to cover the plugin features and benefits.
I don't do demo versions of the plugin, or trials of any kind.
I don't do licensing at all yet, but will do when I move away from Gumroad.
The reason I don't do trials or demo versions isn't because of the complexity of doing it, it's because I don't like them myself. I like to watch a good demo video, then buy the plugin.
Most of the trial plugins I've ever downloaded were never eventually bought. They just languish in trial jail.
The exception is freemium, where the plugin has a demo mode with limited feature set but is otherwise fully functional - no noise bursts, time limit, save limit, etc. I see that as basically two plugins in one - a free one with limited features and a paid one that just unlocks all the features.