This drama is from 2021. HA is still open source and has been great.
The Nix maintainers come off pretty entitled in this one. They ignore advice, requests and do not provide an engineering solution that could solve this without incurring the cost HA would bear. You don’t get to dictate or create work for an open source project that wasn’t designed to play well in your environment. If you want to get it to play nice in there, come up with a proposal that the upstream accepts and implement it. Better yet, come up with a design of your system that accommodates the upstream project. If you go ahead and create that work anyway, upstream can use the tools at their disposal to prevent that.
All decent DP KVMs are very expensive. I got an IOGEAR which is a rebranded Aten. It was also in the same price range. Who knew high resolution needs high bandwidth and high bandwidth signaling and switching is hard…