They're improvements on existing things, which is the basis for pretty much all research. A nuclear reactor is just an "alternative" to a coal power plant, but I'm sure everyone here would agree that the nuclear power plant is better. In the case of the video formats, image/video processing is literally part of computer science.
In the case of React, you could follow the breadcrumbs back to JavaScript, created by a capitalistic company.
Never brought any innovation? VP9, AV1, zstd, GraphQL, React, and many more were made/contributed to by Google/Facebook specifically to improve those services. We benefit from this as they release these programs/formats.
In theory it'd be possible to make a Jellyfin UWP app, of course nobody's made one yet. Maybe it could be you ;)
For Tailscale you just have to install it, start the service, and log in. If you want to install it on just one server and have it act as a gateway to the rest of your network, you can use subnet routers.
It's a mesh network unlike plain Wireguard, and it's much easier to set up (with the caveat that there's a third party involved to coordinate connections and stuff)