Were the mods you were trying to download custom content (e.g. clothing, tattoos, etc.) or “bigger ones” / script mods? It’d be really helpful to know which ones you were trying to download while the crashes occured, if you can still recall some of them
And another question: are you actually loading new mods? If so, what happens to them afterward — after restarting the game, do they remain disabled or enabled? Did you test them?
But generally speaking, 16 GB of RAM is not enough for using a large number of mods. It’s sufficient for the game to run comfortably without significant modifications, but nothing more.