if its covered, then everything from the stay should be covered as long as the facility is covered (and it should be illegal to balance bill you for any out of network providers, if i understand the surprise billing law correctly)
that said it can still cost $1000 per day, maybe more depending on your insurance. i visited one earlier this year and though i was only there for 12 hours, had no meals or therapy sessions or anything, and they didnt dispense most of my meds, they still charged me at least $12000 which came to $1700 or so i think? only because we hit out of pocket maximum before the full charge
basically, if you think you need it, because it's an emergency, then you should go anyway. hospitals often have forgiveness programs and you might be able to take advantage of that. but if youre not in immediate danger, even outside of the financials, i can't say i recommend it (or in many places, whether or not you could get admitted). inpatient is often a traumatic experience, and you should use other resources first if possible. if there's mental health crisis centers nearby you, i've had good luck with those, and at the very least the ones ive been to are free. if you have a primary care doctor, they sometimes have social workers in the office that you could talk to. and of course, if you dont have a therapist youre seeing regularly, that will be infinitely more effective in treating you in the long run (and probably a lot cheaper). a partial hospitalization plan could also give you a lot more freedom and comfort while still having the intensive treatment that an inpatient visit would, and is more effective because it's over a longer period of time, so i'd recommend asking about that first too, if possible.
the hospital you visit will know more about the exact details of coverage, since it differs from facility to facility, so asking them ahead of time is probably a far more effective method of getting information. you or someone you trust could call them ahead of time.