My biggest gripe is that art museums, especially modern art museums, play documentary/clips from documentary that last anywhere from 2 minutes to 30 minutes. Those films are not accessible anywhere else.
I would be very willing to watch them in full, but like most other visitors, I have limited time, especially when visiting a new museum in a different city. If you say observing a painting/sculpture in person is different from looking at a picture, fine, whatever, but making these videos only available in museums is sad.
I always just skip video installations in modern art museums. Because these are usually a bit meh and dated technologically, and you always walk in mid way through some screening of some random thing.
Somehow it never occurs to them to just put that stuff on Youtube or one of the other streaming platforms. I guess that would be a bit too modern. It always annoys me when they have a lot of this going on; especially when the ticket price is high. Usually a sign of a weak curator and exposition. If filling the space with interesting art is a challenge, that's what you do. And the art is why I go there.