[coastflow]

Leave your manager and company for a job at a different company as soon as you reasonably can.

>"I've put in countless hours of work every day (70-90 hrs), being on-call almost 24/7, sometimes for straight 7 days for months despite only getting paid on a salary basis on 40 hr work weeks"

Your team clearly does not care enough to intervene to make sure you are not destroying your health due to your work, and they are not even proactively paying you a fair amount. To be clear: they are not treating you with any respect as a human or person. They have already set the conditions to cause physical health problems, and have already caused psychological problems ("riddled with brain fog").

You do not owe them any loyalty whatsoever, and you should not buy into any arguments (internal or external) that you should stay for any reason; if they cared, you would not be compensated as you have described, nor writing to HN for advice about this.

Cut your hours to make time for interview preparations (if you wouldn't ideally be able to take time off), and start applying to new companies. Changing organizations should be your top priority if you want to change the conditions that are causing your current psychological problems (brain fog, lack of self-confidence, and lack of self-esteem as described in the submitted post).