I own the MT7916, installed in my topton variant x86_64 router, the performance with it is currently disappointing than those off the shelf dedicated AP devices.
Simple test result :
Client is Vivo v2120 getting ~ 123/66 Mbps (DL/UL) on 5 Ghz 160 Mhz
Client is Vivo v2120 getting ~ 50.5/53.6 Mbps (DL/UL) on 2.4 Ghz
Perhaps my topton just cannot support those 3 AMPS power it's required.
Also you need these patches :
luci,openwrt,mt76
My stock firmware Xiaomi AX9000 can beat it easily, my line is 300/300 Mbps, and AX9000 able to top it with 277/242 Mbps at 5 Ghz
For now yes, imho x86_64 router with separate dump AP would be the best for AX.