On Skyrim Legenday Edition, I had a full "SRLE: LotD" setup which entails about 500 or mods (before any merges). It took me two weekends to install and get ready.
For Fallout 4, I run about 150 mods.
On Skyrim Special Edition, I have 200 or so.
The most I have is 40 on Fallout 4, and about a 5th of them are seldom-to-never used. The number of mods I use for a specific character have yet to surpass a small handfull since my mods are more general quality-of-life mods like sound overhauls, textures, better pipboy map, and so on.
So I just finished modding New Vegas from scratch for a new playthrough. I've topped 83 active plugins and 85 plugins total (I have deactivated both New Vegas Bounties III and Better Angels, both mods by legendary quest mod maker someguy2000, as per his instructions until I finish New Vegas Bounties II for III and III for BA).
As for Skyrim, I really must start modding that game all over again... one day. It's a hot mess with loads of mods I added for testing and no playing so it really doesn't count. You should only play "clean" modded games, to minimize potential rages.
By the way, it took me two nights and a few more day hours. It's a lot of work.