First, use Handbrake to optimize your videos for the web. Will save folks watching your videos on data usage and save you space wherever you decide to host them.

Next, go get a paid account at nostr.build if you want a convenient solution. Just upload your videos to your account there and copy/paste the URL to your favorite Nostr client when you are composing your note.

If you want a less spendy option that is a bit more complicated to set up, you can run your own hosting service via spinning up a Blossom server. I am partial to the one built into nostr:nprofile1qyw8wumn8ghj7un9d3shjtnzd96xxmmfdecxzunt9e3k7mf0qy2hwumn8ghj7un9d3shjtn4w3ux7tn0dejj7qpqutx00neqgqln72j22kej3ux7803c2k986henvvha4thuwfkper4sau8ykj 's Haven relay, because you get some very handy personal relays along with it, but there are other implementations, too.