Very Senior Member
The AX201 from 2015 Surface Pro 4 is most likely locked in the Bios.The 160hz is disabled by default, you must have enabled it yourself. It's in the Wireless tab towards the bottom, just uncheck it, hit apply, then reboot the router just to be on the safe side.
I have an Intel AX210 in both my laptops and have 0 issues even connecting to the 160hz band.
The OP has not used the advanced tab to change the adapter settings.