Jellyfin is not designed to be exposed directly. It can be but I wouldn't recommend it. If you are insistent on doing it, I would absolutely recommend engine X reverse proxying with a rate limit to prevent any brute force attacks as well as hiding your family's account on the login screen so not just anyone can see them. Also remember you need an SSL certificate which you can either self-sign or get from a free CA like let's encrypt.

Tail scale works quite well but can be limiting in speed. Your family does not need any technical knowledge. They just sign in on the app and you can add their account to your tail scale domain. Keep in mind you may need to pay if you add more than three, I believe, users.

The third and best option for you in my opinion would be a VPN. It doesn't suffer from the same speed issues that tailscale does. Technical setup would be a bit more difficult than tail scale, but you can do it on your family's device once and it should just always work. Youll need port forwarding, but that's really easy. One thing though, your internet service provider might change your IP address periodically. So you might want a domain name and dynamic DNS, which I would suggest you get from a service called FreeDNS. Like in the name, everything is free, unless you choose to donate , of course. They have it very intuitively laid out where you can use CRON to run a script periodically that just sends a curl ping to their servers so that they know what your new IP address is if it changes. It's a pretty simple setup.