It literally depends on how nice your employer wants to be.
I have a great job now, but I lost two jobs during the covid years. For one of them, my insurance lasted until the end of the next month or something like that, in addition to some severance pay.
For the other, it ended immediately. Like if you have a doctor appointment tomorrow morning that shit will not be paid for. If you wake up sick, maybe call a bankruptcy attorney because we won't be answering your calls.