There's plenty of different hardware out there but not a whole lot of reviews; and my experience with the HDMI interface has, on the whole, not been the best. HDMI is great for consumer stuff, and for plugging in a generic source to a screen (AppleTV, Firestick, Xbox, cable box, etc) -- but, as soon as you want to do anything even slightly more advanced, you often run into hiccups quite rapidly (EDID & handshake/negotiation issues, cable & port quality, HDCP, etc).
I have several 'screens' (TVs) and I wanted to be able to mirror my 'main' display to other screens on occasion, for instance. It's easy to do that with a cheap-ish "splitter" [though they are finnicky), but if you want to "scale" that at all then you rapidly run into proprietary and/or high-cost solutions or have to make substantial quality & capability concessions (and >=10G LAN connectivity is pre-existing).
I was annoyed by the lack of good options & and the extreme prices and/or the limitations of the options that do exist -- enough so that I'm working on (and already actively using) my own IP-based "video distribution" solution, heh.
I can’t say how well a balun/extender setup will work but I believe they make boxes that specifically do that - a combination matrix and extender. I have no issues with HDCP. Happy to answer any other questions.
Search Monoprice for Audio/Video splitters but pay very close attention to the description. Make sure you understand the number of sources and sinks it offers.
Would you care to post the brand and serial for the matrix?
The 16x16 I bought from a small online company called “HDTV Supply” - model number HDCVT4K1616. They were a pleasure to work with.
(Mods please let me know if there are any issues sharing these vendors.)