Comment by tacostakohashi

I've been through phases of this.

Does your company regularly do layoffs (annually or something)? Are you in the US? A lot depends on local employment law.

I would suggest, just show up at 9, leave at 5, try to get a few things done between those hours, but forget 12 hour days and mental bandwidth and being a star performer, just try to detach, punch in, punch out.

If that's not good enough for them, then they can lay you off, and you are likely to get severance, unemployment benefits, etc., etc., it's a better position for you than just quitting and leaving that stuff on the table.

However, you might actually find that by just punching in / punching out, limiting your hours, you can recover from burnout a bit, gain more balance, have energy for things outside of work (be it interview prep or other things).