I don't really hear guilt in your post, I hear worry about your future happiness, and that's a whole different issue, and it sounds like you are conflating a lot of things.
You are FI, which means that you have an enormous range of options.
You are burnt out, which means that no matter what your future holds, you should stop what you are doing.
You love aspects of your work, which means that you may want to do some version of it in the future, but not the way you are doing it right now.
Okay...none of those above factors are incompatible with one another. Quite the burnout job, take some time to work on your mental health, and then regroup and decide what you want to do with your time moving forward.
It's really that simple from what I see.