The G'MIC tool can be installed on Krita version 4.2.2 and older versions.
This tool is an opensource filter framework.
The G'MIC is open-source software distributed under the CeCILL free software licenses (LGPL-like and/or GPL-compatible).
You can download it from here.
Download it, unzip and place it somewhere you can find it.
Open the Krita software and use Settings - Configure Krita - G’Mic plugin and set G’MIC to the file path there.
The official YouTube channel has many video tutorials with this tool and GIMP software.
This is an old video tutorial with one old version of Krita:
