Again, just my opinion, but I prefer Krita to any FLOSS alternative. I’ve been designing professionally for over a decade, using Adobe for most of it; Krita is my preferred FLOSS tool for photo editing, and I’ve tried them all.
I’m surprised, I never managed to use it efficiently for that purpose. Perhaps AffinityPhoto spoiled me a bit. I love Krita for illustration work though, nothing compares… As far as commercial alternatives go, I haven’t tried Clip Paint although everybody praises it- but I don’t really feel the need to. Apparently it’s excellent?