You might experiment with your game-saves. Which is the latest one that will load the game and allow gameplay without CTD? What happened between that save and the next one? Did you add a new mod between those saves?
We ruined our College of Winterhold Quest by entering Labyrinthian early, before starting that quest, by entering the upper-ledge trapdoor-exit at the end of the dungeon, and then by using the platter no-clip glitch to get to the word-wall.
Note that doing this did not crash our game. It simply broke the College quest.
We reloaded an earlier save, from before "breaking in," and our College-Quest then played fine.
If you haven't caused the crash this way, then we might recommend you perhaps find out about how to "verify and validate your local Skyrim files at STEAM," but please be cautious, since STEAM is doing automatic updating too.
We don't know how STEAM updates are bugging players at this stage, and there is a lot of information on these forums about it.
We have found the crash-log useful, as mentioned by @7351Leonidas, but it usually tells us to load an earlier save, though its information often suggests how our gameplay changed after adding a new mod while trying to stay in the same gameplay-sequence with the same character.
Edited by Gorgopis, 28 March 2022 - 05:11 PM.