Archer T9UH AC1900 connects often only to 802.11n and not 802.11ac
my Archer T9UH AC1900 often connects to the Wifi-Router just using 802.11n (2.4Ghz) instead of the much faster 802.11ac (5Ghz). My router supports 802.11ac and when the adapter has established a 802.11ac connection I have a quite fast connection (around 500Mbit). So I assume the problem is not a weak Wifi signal from the router because when I re-connect to the router the adapter usually manages to establish a good 802.11ac connection.
Can I force the adapter only connect to 802.11ac?