I have used various OpenWRT builds on routers... but some times I just want to KISS so this round I purchased
NetGear Nighthawk AX12 AX6000
RAX120
Firmware: V1.2.3.28
Worked for almost 2 years without issue, then noted security vulnerability on SSL so figured to patch it.
Now NAS is broken: - RAX120 - Drive Shares Broken after drive change - NETGEAR Communities
NetGear is very much underwhelming me with their UI... and now they killed features and forum is rather sparse on support.
But in looking at firmware table. This router may not be good option for OpenWRT. I saw a posting with some initial attempts and comments about 1Gb as pipe to CPU 
but.. trying to vet out options before I reach for club.