[nvarsj]

Have you been 10 years at the same company? That is a long, long time. Simply trying something new might be enough to knock you out of your slump. ML is just one niche - why not move to an infra team, security team, sre team or similar? It will be completely new and may reignite your love for engineering.

I'm mixed on sabbaticals. I think the key thing with a sabbatical, for me at least, is it should be treated as doing another job for a while - pick a personal project, some open source you are interested in, and deliver some major functionality on it over a few months. You mentioned Emacs - there is lots of work that Emacs needs for improvement, so it is ripe with things you can pick up and work on. The worse thing for me is just sitting around and doing nothing, that leads me to depression if I do it for long enough.

As others have said, I'd also suggest working on your relationship to work. Seeing a therapist may help with this. If you can find fulfillment outside of work, then the work itself becomes less big in your life and it's easier to avoid burnout.