I just did a bit of testing and was able to create a palette with swatch groups and added the colours in 5.1 on my linux virtual machine. Then transfer the palette to my google drive. Then imported it back into Krita 5.2.1 on Win 10 and it did keep the groupings. For some reason I couldn’t get the shared folder working between my VM and Host but whatever so that’s a work around. I’m going to try to install a previous version of Krita on the Win 10 PC just for the palette creation.
Installing the previous version it wouldn’t allow it however you can download the zip. Go to the Krita.exe file in the bin folder and it can run from there. You can only run one at a time I did try to get both running it didn’t work but they do both access the same palettes folders so in that way it would be easier than running a VM if you want to create palette swatch groups.
HTH