There's PhotoGIMP to make the transition easier, and Krita I believe has the option to switch to Photoshop keyboard shortcuts, but if your criteria to switch is an exact 1:1 clone, then I believe you'll be stuck with Adobe forever. As with any program switch, a little learning is necessary, and there's many excellent tutorials available on youtube to make that switch easier.

Only if devs try to work together.

Consider donating to them! The devs of open-source programs are often trying to replicate what billion dollar corporations are doing with a budget a thousandth of the size.

The pros who changed over from FCP may be interested to hear that. As with anyone who did 3D animation who had to change the workflow they used. You do allude to the incredible lock-in that Adobe’s de facto monopoly has generated, though.

Workflow should be seamless.

As if they match between "pro" applications.

Sorry this thing isn't exactly like that thing, but if you were already used to this thing, you'd never worry about the program and all your work being remotely deleted.