Only Murders In The Building, theory, major spoilers
Dunno if I'm the only one here watching this, but... I just want this down for the record so I can bookmark it and come back to it later.
Everybody seems to have settled on it being Jan, Theo, or Teddy. I think they've fallen into the classic trap: they've assumed it's just a single person.
In my experience, "multiple people did it" is a VERY common murder mystery trope and they're ignoring it at their peril.
It's also generally the most satisfying option-- it's complex, it's poised to take maximum advantage of all the clues, and it drastically lowers the chances of fans getting to the solution before the show.
This is going to have been a team effort. I'm betting Tim was killed by a series of events with multiple agents, possibly a Repo Man-grade chain of weird coincidences. Perhaps, for instance, Teddy poisoned some dips and Jan (unwittingly?) conveyed them to Tim?
I just don't buy that someone like Steve Martin would be unaware in 2021 that the fanbase could get way ahead of him. He was one of the very first stand-up comedians to approach his art with an abstract philosophical theory-- *specifically* one about depriving audiences of their natural expectations for as long as possible.
Of COURSE someone during the production of the show, if not necessarily Steve, would have noted that fan communities are *incredibly* aggressive and effective puzzle solvers. So there is just no freaking way we are going to get a single-variable solution to Who Has Done Did The Bad Murder Thing.