it's 4.30 minutes long, although I've seen nostr:npub1qny3tkh0acurzla8x3zy4nhrjz5zd8l9sy9jys09umwng00manysew95gx sharing long format vids. I've just downloaded Olas to see if that was an option but the UI is glitchy/buggy.
Discussion
What version of amethyst are you using? And what file host when uploading the videos?
Nostr.build has a 50mb limit.
Try using nostr download one - it worked for my huge Pokémon match video.