Home Internet and wifi extender

I tried 3 different high-end extenders, including a wifi 6.  I got all 3 to work easily with the 2.4G range, but none of them would see the 5G range and that is because of the fixed channels that the new Arcadyan KVD21 Gateway uses are not seen by any of the wifi extenders I tried and very unfortunately the Arcadyan KVD21 Gateway has very limited admin functions available within the UI page.  I would like to see an official response from T-Mobile on this and would actually like to see more control given to us in the Admin config UI.  The range on the 5G from the Gateway is extremely short and poor, even for 5G, which I know is much shorter than 2.4G.

Gracias.