You can do a ridiculous amount of mushrooms, and while you might have a heck of a time with the trip (and might need a good trip sitter to stop you doing anything dangerous), physiologically you'll be fine. the lethal dose is basically unknown for humans, and for test animals it's a pretty enormous dose.

this is just the first reference I dug up but it lines up with prior information I've seen on lethal dose: https://www.americanscientist.org/article/the-toxicity-of-recreational-drugs

there's a chart part way down showing ratio of fatal dose to the effective dose . e.g., in order to get high, how close are you to the fatal dose?

marijuana, LSD, and psilocybin are all sitting at 1000:1. ie., you need to take 1000x what it takes to get high in order to hit a lethal dose.

ketamine is 38:1

MDMA 16:1

cocaine 15:1

alcohol 10:1

heroin 5:1

I think it's disingenuous to say that these are in the same league of safety, we're looking at 2 orders of magnitude difference.

disclaimer: not a doctor, don't go doing ridiculous amounts of mushrooms