I believe the EMTALA means a hospital can't deny you emergency treatment. Though what defines an emergency can be kind of murky. They could certainly evaluate most covid patients and send them home with Tylenol, or make them sit in their car while they let gunshot wounds in. I also think there is government money available for hospitals treating covid patients, so it is in the hospital's interest to not turn them away.

Some anecdotal evidence, I went through cancer treatment starting Feb 2020, ending Feb 2021, with a few scans since. Including one in a few days. I have never had any of my numerous appointments postponed for covid. But I think it is because I am lucky enough to afford to be treated by a hospital with a large cancer department.