Part of the problem here is that VSTs are stored in several different places depending on the type (VST2/3) and the vendor's choice.

This is a search from Linux of my Windows C: partition for folders for VSTs, i.e., folders having a name including 'vst' in any mix of case.
I doubt that this is a complete list. (Actually, I know it isn't because BIAB's bb/Data/libx64 is not there.)

$ find . -type d -name "*[vV][sS][tT]*"
./Program Files/Common Files/VST2
./Program Files/Common Files/VST3
./Program Files/Common Files/VST3/sforzando.vst3
./Program Files/Common Files/VST3/Surge Synth Team/Surge XT Effects.vst3
./Program Files/Common Files/VST3/Surge Synth Team/Surge XT.vst3
./Program Files/Garritan/ARIA Player/VST
./Program Files/VstPlugins
./Program Files/Native Instruments/VSTPlugins 32 bit
./Program Files/Native Instruments/VSTPlugins 64 bit
./Program Files/Plogue/sforzando/VST
./Program Files/Steinberg/VSTPlugins
./Program Files (x86)/Common Files/VST2
./Program Files (x86)/VstPlugins

Jazz relative beginner, starting at a much older age than was helpful.
AVL:MXE Linux; Windows 11
BIAB2025 Audiophile, a bunch of other software.
Kawai MP6, Ui24R, Focusrite Saffire Pro40 and Scarletts
.