I just made a mirror out of two NVMes―they got cheap enough not to bother too much with the loss of capacity. Of course, that limits what I can put there, so I use a bit of a tiered storage between my NVMe and HDD pools.

Just think in terms of data loss: are you going to be ok if you lost the data between backups? If the answer is yes, one NVMe is enough.

I would not recommend unifi for a mature solution. It sure works nice as a glass panel, but it will get limiting if you will have a desire to hack around your network. Their APs are solid, though, it’s just the USG/Dream machine that I wouldn’t recommend.

Mikrotik software is very capable and hackable and you can run it in a vm if you feel like bringing your own hardware.