@Badger Replying to myself as I have found a solution for my version of this issue. When my ISP is down, I change in Deco app the mode it's supposed to function as. (Mine is in Norwegian so unsure...

@TP-Link So this is probably why I cannot locally access my Jellyfin server without internet? I'll be renovating soon and will have to tear down the entire living room (ISP router will be removed)...

I have three m9+ around the house. Main Deco is in the living room, connected to my service provider router, in bridge mode. I have gigabit fiber, 1000 up and down. Speedtest performed in the Deco...