Blossom would work however its not quite there yet, You would have to encode and optimize the videos yourself and they would only have one resolution setting

There is the option of using HLS (which is what twitch uses for providing multiple resolutions of a video) with blossom or any other hosting service, but you would still have to convert your videos to HLS which is even harder than mp4 😞 

I think nostr:npub1v0lxxxxutpvrelsksy8cdhgfux9l6a42hsj2qzquu2zk7vc9qnkszrqj49 was working on HLS in zap.stream and nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s was also experimenting with encoding videos to HLS  nostr:nevent1qvzqqqqqqypzqvhpsfmr23gwhv795lgjc8uw0v44z3pe4sg2vlh08k0an3wx3cj9qy88wumn8ghj7mn0wvhxcmmv9uq3kamnwvaz7tm5dpjkvmmjv4ehgtnwdaehgu339e3k7mf0qqsxhezqs2vd9e5jcgg9u5jwa94da49xv4pz7vdek8ca2atgx426ajsmfx8yj

I also created a hacky experiment for uploading HLS videos to blossom https://github.com/hzrd149/blossom-hls-upload (sorry there are no instructions)