They are all non-destructive in Krita. Just use a transform mask and go to tool options, select liquefy and after you liquefy however you want you can just hide the transform mask and it stops liquefying the layer.

Yes, Krita has had this feature for years. Non-destructive filters (adjustment layers), too.

GIMP still doesn't have it. Only in 3.0 it got adjustment layers for filters.

Oh, this is news to me! I've used Krita to pain (recreational noob, not on a professional level) and I never realised this. I'll play with this tomorrow