My honest advice?
If you tried all that you could, and still recceive crashes, its time to nuke your skyrim, and reinstall completely.
Trust me when I say the stress of trying to play a fun game that crashes too many times just when you're having fun is far more than just starting from scratch and reinstalling your mods again.
My second advice. If you go on ANY mod that has a bunch of unanswered bugs with no fixes from the mod author, or any mods that have like 6 foreums flooded with users complaining of ctd and bugs, thatt the mod author neglects to fix, or even if you see that the mod hasn't been updated since 2012, and this mod uses a lot of scripts.
My advice is to
It means that mod is more or less going to give you issues as well. 9 out of 10 the reason you ctd so many times, is propbably because you're using one of those mods that are having issues that went unaddressed. If you see there is no bug or forums on the mod site, go into the posts and see what others commented. A locked comment section is also a severe red flag something is going down.
Mods over on the loverslab side (besides sexlab) are also bound to give you your heaviest crashes.
Heavy scripted mods, or mods that add a whole bunch of npc to your game will more than likely cause crashes.
This is the true way to have a fault free skyrim game, just because skyrim within itself is buggy.
Even with USLEEP you're still bound to have crashes the more of these types of mods you have.
Skyrim is severely outdated as well, and we all know bethesda is known for being buggy programers.
Your best bet is to ensure these things are in order before things go wrong.
With that being said, you may find that you download a mod, it goes fine for months, so you download 50 more mods, only for your game to all of a sudden start ctd; that one mod you thought was good could be starting to bug out again.
Also, these guys: G.E.M.S Gameplay Enhancement Mods for Skyrim.
A good bit of them have severe issues; whose website isnt even active anymore when you click their logo.
Its a high probability that they could also cause ctd; I swear by their hunterborn mod, and never had issues.
Also, with that all being said sometimes its literally not even the mod author Sometimes its just the mod users, as they do things like install a script mod manually---never do this, this is bound to give you issues, making it tougher to uninstall, and if so not all scripts might be removed, you'll need to go search for those. I cant tell you how many times I read a weird off the wall issue a mod user was having that I had no idea how to fix---like they'll say everytime they jump up in the air, they crash, despite the fact that their mod that they used was a realistic needs mod not even touching jumping. Things like this is also a problem, and can easily overwhelm mod authors who don't know who to help first. Sometimes not even other mod authors will help them solve their mod's issue either, and so they're at a loss for words like everybody else.
Use a mod manager---vortex, nmm, mo, anyone just use one. The only mods that are ok to install manually, are ones you're certain wont give you issues like realistic needs,
a house mod, clothing mods, ect.
Even mods like Bruma beyond skyrim can be installed manually, but mods like wet and cold, I wouldn't install manually. Hopefully this paints a clearer picture
really wise and valuable advice for mod users, very thanks!