Poor Performance from Clients

[BeastleeUK]

What happens when you disable tailscale on the jellyfin server?

OK, so this sent me down a long dark rabbit hole with many twists, this included no access to anything on the LAN when I turned off the TS VPN on the server!

Basically I had local the subnet advertised so that I can access devices on the LAN when I am away from home, Tailscale on a standalone server doesn't like this when you stop the VPN service, LAN clients can't connect.
I also had split-dns with Cloudflare presenting CNAMEs to the TS IP of the server and my PiHole DNS, which was what TS was pushing my domain lookups to, was the LAN address. By disabling the subnet advertising I couldn't make DNS queries about internal services because the DNS server was the LAN address and the results were too. I've had to remove the split DNS and just leave the Cloudflare records to the VPN IP in place. This seems to be working so far. But there's more...
I have IPv6 enabled and the DNS for this didn't look right when I checked it, I then found that I'd entered it with 1 wrong digit in my DHCP service, although this wasn't actually a part of the problem it needed fixing. I went ahead and updated the DHCP entry for IPv6 DNS and saved the config...and then my ISP changed my assigned IPv6 range but again only one digit had changed. It took me a while to work that one out!

So now I can access quite happily over Tailscale from my phone when off LAN. My web clients work fine on both and my Fire TV works on the LAN. One of the LG TVs is OK but I think the wireless card is now flaky and I'll update once I can check the other but I think it will work exactly as expected.