There used to be a little note (gone now) about Windows Gimp version 2.10.28 (and above) and pre gimp_gmic_qt 3.0 not working due to a dll incompatibility.
For Gimp 2.10.30 use the latest Windows plugin from http://www.gmic.eu
For Gimp 2.10.30 use the latest Windows plugin from http://www.gmic.eu