Tomb of Horrors gets a bad rap, but it can be a really fun one-shot in older editions of the game. (It has an infamously bumpy start.)
I remember a fun night in the early 90s when my college roommate and I ran through that adventure at a friend's birthday party. (I was already familiar with the tropes and pitfalls, so I kept my mouth shut and let my fellow players "enjoy" the dungeon's many deadly surprises. Even so, my cleric didn't make it out alive.) But it was all good; we just rolled up more characters and kept going.
It was a lot of fun!
The 3rd Edition reprinting of it, not so much. After spending over an hour rolling up your character (seriously, creating a 3E character at that level can feel like filing your taxes), nobody was amused to watch them get annihilated before they could finish their first beer. And the idea of "just roll up another character" was laughable.
Tomb of Horrors only works when you have zero attachment to your PC - it’s essentially a high level funnel to use DCC vernacular.