What you may want to do is use something like Tailscale (or a VPN) to connect the two sites (homes) together.

Run your Tailscale setup in home A, and then in home B connected to your tailnet. You can install Tailscale on the home router of home B, or install it on any device that needs to connect to home A.

Then in home B you just connect to your Jellyfin server like you normally would if you were in home A. This could be a android box or smart tv for example or accessing it through a browser on a pc. (If those devices have Tailscale installed and are connected to your tailnet in home A)

Using a VPN like Tailscale would also mean you don't expose your Jellyfin to the internet.

Side-to-side Wireguard VPN if you want to keep it simple service wise. Tailscale/Headscale vor Netbird if you want a relatively easy way to set it up and are okay with a bit of overhead.

i use netbird. i gorgot why i did not choose tailscale but netbird ine my research

Tailscale and the other tools people mention is an option.

Another one that’s a bit more costly unless you already have it is UniFi gear can do site-to-site VPN which can make it pretty easy as well. Other router gear has it as well, UniFi just makes it easier. This would put each others networks next to each other and you could access them as if they’re in the same home.

And then of course just wireguard direct connection.

There’s a lot of options, matters only how DIY you want to make it.

Unless you have fiber at the house with the server, you’ll probably run into issues with streaming these ways without transcoding, even with transcoding gear… cable upload speeds and reliability can be middling.

If it is in two different houses, why would you use a NAS as a client for jellyfin ? You'd better connect an android TV box like an nvidia shield and connect to the jellyfin.

Of course, the jellyfin instance should be accessible over the internet, either by setting up a reverse proxy or a VPN.

Advertise/present the services to the internet, or merge the networks or devices together using a service like Tailscale.