You have 3 options

1) By default if you are using Primal then it uploads in the primal blossom server, I dont know size limits maybe depends on membership

2) Run your own blossom server.

https://github.com/PrimalHQ/primal-blossom-server

3) If you already have a media server like Plex/Jellyfin (self hosted) then use cloud flare tunnel and directly share the link of the video in Nostr note.

Nostr relay only stores link so it's not heavy on relay.