Could do with a bit more info: Is the Gimp 2.10 from otto-kesselgulasch-gimp-edge PPA or is it a flatpak.
If from otto-kesselgulasch-gimp-edge then he also maintains versions of gmic as well. gmic 2.2.3 at the moment. Get that from the Mint repo.
Otherwise manual installation.
1.
https://gmic.eu/files/linux/ where you can get the last of the stable 2.2.x QT series as a zip

2.
https://gmic.eu/files/prerelease/ where you can get a QT ver 2.3.x as a zip

There are also .deb packages there that might/might not install
Unlike Windows gmic_gimp_qt unzipped is a single file (about 8 MB). However there are QT5 dependencies which might not be installed in a 32 bit XFCE. You will have to try-and-see and install QT5 from the MINT repo as required.
Flatpak? I use one of these in Kubuntu 64 bit. QT version is not going to work. An older GIMC-GTK version 2.2.4 with a couple of additions can work but I compiled that one myself.