@ Musicbear. He is talking about Linux vst.
Not to long ago I did not know myself these exist, but there are Linux vst. Like Amsynth.
https://amsynth.github.io/
amsynth 1.5.0 AudioUnit for Mac OS X
amsynth 1.8.0 source code for Linux (VST / LV2 / DSSI / JACK / ALSA / OSS
No windows version.
That synth can be a stand alone or a vst.
I have not succeeded yet but have been trying to use Carla to load Amsynth vst.
That in theory should work, at least on Linux.
I think windows users are out of luck here, because there is no windows version of amsynth as far as I know.
On windows you should also be able to use carla to load vst though, just not this one.