Xbox OneX - slow wifi speed

Hello masters,
about week ago bought ax3.
Till now I used 15y old netgear with 8y old Unifi AC lite.
With AC lite download speeds goes max about 500mbps so decided to upgrade.
With ax3 notebooks and phones is going very well, speed is about 700-900mbps.
But Xbox has maximum at 50mbps (with unify it was about 300mbps).
Tried almost everything that could have some effect on it.
No matter if using 2.4GHz or 5GHz, but using only 5Ghz.
Some xbox gamers here, or somneone have sugestions?
Thanks.

To reduce interference with neighbors I set up static frequency.
add band=5ghz-ax disabled=no frequency=5500 name=channel100 width=20/40/80mhz
/interface wifi
set [ find default-name=wifi1 ] channel=channel-100 channel.band=5ghz-ax .width=20/40/80mhz configuration.country=Czech .mode=ap .ssid=5G disabled=
no security.authentication-types=wpa2-psk,wpa3-psk .ft=yes .ft-over-ds=yes

Was the unify device wifi6?