Well, I manage to get 350 Mbit/s down, 220 Mbit/s up on 80 MHz AC (@-70 dBm, so I guess ax should not have any advantage) through 2 walls (and laptop kind of hidden behind a monitor) with the WAX206. So... I rather promise the conservative option 
I have the WAX206 on order, the lack of USB is a bit annoying, but now I know I will be supporting the most FOSS friendly chipset, makes me feel better about the purchase.
The 2.5gbit port may or may not prove useful as well for me in future, I have a 1.1gbit internet connection, of which the modem has a 2.5gbit port to allow a LAN to get those speeds, but my LAN is currently all gigabit. Many ISPs in my country are currently also trialing 2gbit internet services.
Currently my games consoles are not wired, and max out my C7 at around 230-250mbps, they are really close to the AP, so I am hoping the upgrade will net me at least a doubling of their speeds.