Upgrading Unifi System, What are my options for Protect?

So, I'm upgrading my UDR OG to a UCG-Fiber and associated fun accessories for my network. The UDR OG is going to my MIL in her new apartment after her ISP shows up. But I'm also planning on building out a 10" rack with all the goodies for my home.

The issue is, the amount of UI cameras I want to use exceed either the NVR Instant or UCG-Fiber. So my question is, what are my options, 2 NVR Instants? Outside (4K) cams on the NVR Instant and the inside (HD) cams on the UCG-Fiber if that is possible?

Thoughts and ideas on how to keep this inside a 10" rack would be appreciated, I dont have the room in the closet for a 19".