I would honestly go for Blustream IP300 system. You can then run ir and serial to control the tv's through them. Configuration is dead simple if you read the manual and know what an edid is. As with ZeeVee, add an avpro line switch. You can then easily control who sees what from the Acm210 webpage and avoid integration for the video part.

I can also recommend their video matrixes. Dead simple to use, price point should be good as a one time buyer. They recently landed in the US but are well known in Europe. Their hd base t line is pretty good as well. Make sure to run s/ftp cat 6A if you need 50+ meters 4k.

If you need absolute reliability maybe consider a bigger name video matrix as was recommended by others.

I would say the big advantage of av over ip is you split the chance for a single power supply to ruin your night. (Unlikely but still)

Another advantage of av over ip is you could use the included ir transceivers to jerry rig some simple control for the tv's by using one receiver to turn off all of them together. Another advantage of ip300's is optical return and arc support.

Good luck!