I have friends that came over from Europe for hospital stay - they got the bill, sent their objection and the hospital reduced to the usual 35%.
If you live in the US you always can buy insurance that will cap your max out of pocket to about $8k pre tax a year. Also if you’re employer doesn’t provide insurance - you’re probably in an “entry level job” that is not meant for long term employment, but rather quick money for young adults, who are still on their parents insurance (up to 27yo)