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.
Audio/video contractors are absolutely a thing. It involves a lot of TV mounting, but there’s usually a lot more behind the scenes.
Source: I am one