I don’t think desktop Linux works for you. That’s the truth. You know, I was like you, and so was my husband. These individual projects that never felt that they fit together to create a cohesive product, always bothered me. So what you’re asking, will never get fixed, to be honest with you.
But speaking about myself, I decided to use Linux because it’s the right thing to do. As a painter myself, who needs some of the features Photoshop has but Gimp 3 doesn’t, I feel you. But still, I use Gimp now, 100% of the time. I settled for less, because again, it’s the right thing to do. I have no interest to use Windows and its spyware. I have a macbook air with macos for occasional browsing (I like the hardware), but again, I use OSS software on it (including gimp). The rest of my 5 laptops and 3 desktops, all run desktop Linux. I’m more often on an old Macbook Air from 2015 running Linux Mint, than I am on the new Mac running MacOS. My main desktop is Debian-Testing. Is it as cohesive as Windows? No, and it will never be. But again, it’s the right choice.
Thankfully for me, I don’t work anymore, so it’s easier to move to Linux. But my hobby (painting), it’s done in a less optimal degree with Gimp, yes. And that’s ok with me.