I've heard of the ZeeVee, its a great idea, but it also costs approx CDN$ 1,964.75 on some online marketplaces. that is a lot of money to spend to distribute an hdmi signal over coax to multiple tvs. is the op willing to spend that much? we dont know, only the op knows.
The model I quoted is the latest. There are many older models around, therefore much more affordable.
Some need RGB Inputs but all are very reliable from my experience and almost infinitely expandable.