Dealing with burnout from long review process
I can suggest two things. The first, and probably most important, is to have other things to occupy your mind and your time while the process goes on. Don't wait for replies on submitted work, but get the next thing into better shape.
The other thing is just to accept that the system is out of your control for all practical purposes. Editors and reviewers (especially) have their own work schedules and you have no control over that. The quality of the reviewers is not something you have any say over. When you do get a reply, respond promptly, of course. And if you find long delays between communications, ask about the status and ask for an estimate for completion of the current stage. But just accept that it is a fact of life, not unlike the weather.