If it’s cable internet and not fiber/DSL, I’d look at connecting the ISP’s coax to the house’s coax. Provided all of the house’s coax ports are connected to a splitter, you could feed the ISP coax into the nearest port and plug the cable modem into the office port.
There’s a plugin for Jellyfin that will analyze the audio of your content to automatically tag intros, recaps, and credits