You can upload short videos to https://nostr.build
Discussion
Do you know size limits. Looking in TOS but can't see it
Haven’t seen it documented, I did get rejected earlier with a 90 second video. Shortened to 20 or so and it worked. Was HD video from an iPhone.
Whatever the limits are, I suggest you always try to compress videos as much as possible. Currently Nostr clients are not super optimized and consume a lot of bandwidth by themselves, so posting +10mb videos is not the best thing to do. Especially for anyone using Nostr through mobile networks. For large videos there is also an option to share embedded youtube links.