gmic-gimp-qt does throw up an error in Windows Gimp 2.9.6 Seems a problem with libcairo-2.dll There is a temporary fix if you read through:
For installation, the .exe installer will try and add it to .gimp-28 Edit that to ‘another location’.
Add the path to ‘another location’ in Edit -> Preferences -> folders
Edit: Normally I use linux, compile my own gmic_gimp_qt for Gimp 2.9 so no problems.
Trying that fix in a Win 10 VM and still get a whole list of errors from gmic-gimp-qt. Looks like Win users need a gmic-gimp-qt update.