With my repo (and I’m sure The Ben’s repo will follow up), Blossom will work OOB with a simple docker/podman compose up – just give me a few days. :)

As for Mastodon, if you already have an Object Storage and is serving the media from a separate subdomain you’re golden; there's plenty of video-friendly CDNs out there. I self-hosted for a couple of years for $6 to $15 a month (yes, there are some great managed hosting options that actually do a proper job of giving you a solid backup if you need to check out your data at that price range, I myself surrendered to the convenience after self-hosting for several years).