>Telling your home router to forward 445 is not that hard
At first I thought this was sarcasm...
Dont do not... putting samba or any other SMB server on the wider internet is a bad bad idea. It is a good way to get your system compromised.
>>& tablets should just be able to connect over SMB
The draw of Emby, Plex, and jellyfin is not just to file browse and open up files
They Provide Meta Data about the Media, Play Series in proper order, Allow you to see rankings, Ratings, provides Art, etc and most importantly Keeps track of play history on a per user basis.
SMB would not do any of this.
>>Tailscale's the only company on the planet who seemingly has the sense to extend our homenet's reach quickly/easily.
Yes and no. VPN's have been used by home users for a long time, and tailscale is far from the only company / project doing what they do [1]. Tailscale was made possible do to a new(ish) VPN protocol (wiregaurd) that is very light weight and secure, previous VPN systems like OpenVPN would not be able to support something like tailscale
[1] https://lwn.net/Articles/910766/