That's abnormal, it shouldn't be like that. My flatpak rarely has updates (compared to Arch/yay) and they're quite fast, still less than a minute even if there's updates to the NV libs (I didn't time it). There must be some kind of particular issue? What's your setup?
Looking at it - I got flatseal, chrome, firefox, thunderbird, dropbox, steam, joplin, cryptomator, mesa, NV libs, gimp, discord, resynthesizer, libreoffice and some other bits on flatpak. It's on an SSD, Internet 150Mbps. Is it installation or download that's slow for you? With it being 20min I would guess there's a problem with the download speed from the server, routing issue to flathub, etc? Flatpak is not that much of a slog.
I would call that an exaggeration. It's not perfect sure, but it has finally improved a lot in the last year and it works for some. I had to get a new gaming laptop earlier this year and the only good option I could afford had an NV card. It was a great deal from Bestbuy certified open box, $500 off (I love those open box deals with 30day return).
It works well, I play Guildwars2 and BG3 flawlessly through XWayland+proton with great performance. Maybe it works well because I put it into Dedicated Nvidia mode, instead of using Optimus? (I never liked Optimus)
Sure it's not perfect, I get graphics glitches in KDE if bringing the laptop out of sleep, funny colors and a mouse with a funny trail, but I don't need to use sleep, I boot it in the morning and shut it down in the evening, it's no biggie for my use-case.