When I was younger I went and bought a new modem so I could play halo on my Xbox in another room than where my parents had the original modem. Found out then I’d need to pay for each modem.
When I was younger and before WiFi was a thing I naively thought I’d just plug in a new modem.
https://en-us.support.motorola.com/app/answers/detail/a_id/1... will give you some additional info.
My house had quite old (likely 1980s) coax home runs and it worked flawlessly. All I did was change out the entry (root)splitter for one that had a point of entry filter. I’m not sure that was even needed, but it seemed sensible and was not expensive or difficult.
Usually those can be found in the wall boxes behind the plate - but not always!
These used to be a bane on cable modem installs for apartment complexes, but the situation should generally be better 25 years later...