There is a nice workaround:
https://www.gearslutz.com/board/showpost.php?p=10271586&postcount=840
https://www.kvraudio.com/forum/viewtopic.php?p=4884031#p4884031
There are VST3 Wrapper out there. You just need to put these files from the “Gears” sub folder to your VST2 folder:
vst3shell.x64
vsti3shell.x64.dll
vst3shell.x64.core
After rescan in Renoise, there should be all VST3 effects and VST3 instruments available. Seems works to great.