Did you know that NewTek's VMC, which can handle 44 UHD 60p NDI inputs, is running on an i9-7920x and a GTX 1080 (or equivalents)? Obviously all those sources aren't pulled in full resolution at the same time, only those few that are on Program and Preview buses are. The rest is pulled as 360p proxy streams, to feed the multi view. If you could spend some time and incorporate that and other optimizations, and in the end be able to recommend an RTX 2070 instead of a 2080 Ti for a basic 16-input 4K build (noting the limited number of sources that can be on outputs at the same time), that would be a huge step forward.

Handling that much bandwidth is exactly what I don't want. I want the proxy streams to be utilized. TriCaster TC1 with 16 UHD inputs has only two 1GbE ports, which is enough to pull 4 full-resolution sources at the same time. That poses some limitations, because you won't, for example, be able to transition on the main M/E from an M/E with three UHD layers to another M/E with two UHD layers (I'm not sure how exactly they deal with that), but knowing this limitation, you still get a switcher that can have 16 (or 44, with a bit better specs) sources ready for you.