I had/have this issue too, in my case Discord halts the shutdown. My workaround is just closing (not minimizing, closing!) discord before shutdown.
Discord is not usually opened, since I don' t use it regularly. So this is not it.
I have a hybrid Intel/Nvidia laptop too. It has never worked right, and I regret getting it. The amount of time I've spent troubleshooting graphics issues through the years...
Yeah I doubt I will ever get another laptop with hybrid Nvidia/Intel again. Support for it has become a lot better over the years, though. I remember I used to have to log out and back in to switch between the two graphics cards.
Anyway, I found this on the Nvidia forums. The problem described is slightly different, but I think I will try this and just see if it happens ever again.
❤️ Debian
Rules