I'm using Blossom to host videos, specifically using HLS so the video is split into many segments - of varying bitrate and quality - and so a 'dumb' HTTP file server like Blossom works perfectly
All the complexity - e.g. adaptive bandwidth use - is client-side, but hls.js is an effective library to make it easy to develop
In my use case, I'm developing a 'Cashu payment channel' which allows tiny Bitcoin payments at very high frequency and therefore a streaming video service where you pay per second is a good demo.
(I feel like I may have misunderstood you a bit. What do you mean by 'formatted'?)