The “fixer” proceeded to fire 70+% of the team over the course of 6-8 months and install a bunch of …

Out of curiosity, it sounds like you're the kind of person that could easily find another job. Why slog it out until the end rather than quit/find a better gig? Genuinely interested because every time I've ended up with a manager like that my mental health has suffered so now I generally start planning my exit as soon as I'm stuck with a bad manager.

In my case at a different firm, I happily gave notice than to put up with the "fixer", who had been hired by the other "fixer", both of which were mostly only good at shitting all over the place and driving most of the technical organization out of the company. I got the feeling that was the whole point, so I resigned instead of waiting for my eventual layoff.

As someone who now lives and works in Denmark: it's sad that so many of us have been conditioned to think 6 weeks severance is generous. Here, labor unions are quite widespread, and very effective at negotiating reasonably but firmly. As a result, I can depend on 3 months severance _guaranteed under law_ after 6 months at a job. (After 3 years, it goes up to 4 months, and then from there up to a max of 6 months.) It puts the responsibility for risk of instability, errors in planning hiring / capacity, etc. firmly where it belongs: with the employer. (And no, the economic sky is not falling here as a result. Quite the opposite.)