Time to quit. I'm pretty sure this is not legal.

I mean, it might suck if you don't have anything lined up right now - But quitting seems like absolutely the thing to do here, because that sounds absolutely hellish. I suppose that kind of schedule might be offset if they're actually paying you proper overtime, but I'm guessing from the tone here that they absolutely would not be. But yeah, quit and let them realize that proper staffing includes planning for regular downtime as required by labor laws.

Make sure to check in with someone who knows labor law to make sure what your rights are. Either they’re not allowed to do this at all, or they’re required to pay you an arm and a leg so you can take a nice long vacation sometime else in the year.

depending on local labor laws, you can probably just say no. if it goes above overtime limits its illegal and you can say no/ report the company.

That's definitely illegal. Report them.