After years playing Skyrim I faced that situation, too. Searching for answers, someone explained that turning the Antialiasing off in Skyrim launchercould solve the problem - and it really solved the problem!
The same problem for me. I have more than 100 mods installed and, just a few days ago, I started getting CTDs while sleeping, waiting and fast travelling. It is really annoying! :mad: I will get rid of some of them and try again.