I wouldn’t know how to access Jellyfin through tailscale on a Android tv that is not in the same network, and that wouldn’t necessarily be sharing.
I think the most relevant thing is that using DDNS implies exposing to the internet which for many self hosters is a big no no. As well if you only want one or two machines , maybe tailscale can be a very easy way to setup… I guess it boils down to the OPs needs.