@TpRoll

The photo you uploaded does not mean that Deco is using just the B7 band (which is a 4G band).

I see form your 2nd photo that your Deco is connected to a 5g band (probably N78), but it is doing so in NSA mode by aggregating 4G bands (one of them is B7).

NSA means Not Stand Alone 5g, which means it needs to aggregate 4G bands to achieve 5g connection.

SA is the Stand Alone mode which connects to 5G without the need of 4G bands but this is still in primary phase and not so common.

If you scroll further down in your 2nd photo you will see "more information". Click it and it will show to you the 4G bands that have aggregated as well as the 5G band to which you are connected to. You can upload a screenshot of your "more information page" and I can explain what it all means.

Fyi most common 4g bands are B1, B3, B7, B20. 

Most common 5G bands are N1, N28, N78.

P.S.: All above being said, indeed sometimes the x50-5g decides to change to another 5G band if it picks up a stronger signal (i.e. from N78 to N1 or N28), even if you have set N78 as your preferred band. I have created 2 threads about it and I hope this will be fixed in an upcoming firmware update. The only way to make sure it does not change band is to cell lock it. But this also locks the PCI of the band, so if the PCI changes during the day (i.e. you get better signal from another tower), it will disable your 5g band and use only 4G bands, till it gets back the 5g signal with the same PCI. If your PCI is stable all day/any day, then you can cell lock it and fix your connection to the exact band and tower that serves you best.

  @madvinegar Hello thanks for the info. I'm sorry I was ignorant and frustrated. I've been fighting with routers and antennas for a long time. Going crazy 🤣 

Here's the additional info

I would like to cell lock N78 or N3 but it asks me for numbers I don't know

This is my BTS. Others are too far so I'm guaranteed to connect to this I think.

  @TpRoll 

Indeed you are connected to 5G band N78, and to the aggregate of the 4G bands B7, B20, B3 , B1. Please see the red highlights the below picture.

If you want to cell lock band N78 you need to complete the following info:

NRARFCN: 638016

PCI: 846 or 724

As I explained in my previous post, the PCI may change during the day(s) according to the signal of different cell towers. This is why I ask from TpLink to issue a firmware that will properly lock the band, not the cell (as the PCI changes).

For the time being, just select N78 in the "preferable band" option and see how that goes.

Hope I helped.

Thanks I was confused by the UI listing only a 4G band. I learned something.