Uverse wireless cable boxes lose connection when PS5 is turned on.

You could switch to a Nintendo Switch or XBOX.  Just sayin'

Nintendo switch works fine when connected, no issues with the cable boxes.

Exactly:  No PS5, no problem. 

But, seriously, the PS5 is connecting to the Gateway's Wi-Fi?  When "directly" connected via Ethernet, is this also directly back to the Gateway?

The customer service had us try both, they even set up a guest network for the wifi for just the ps5. Otherwise we had it directly connected to the gateway via ethernet cable. Both ways, as long as the PS5 is on, none of the wireless cable boxes will connect to the network. So Strange and frustrating!!

 If they set up the Guest Network, which is 2.4 GHz, and you still had trouble with the Wi-Fi connected TV Receivers (which are always 5.0 GHz), then I'm thinking the issue isn't in Wi-Fi interference, but maybe RFI going through the power lines from the PS5 to the TV Receivers making them not able to process the Wi-Fi.  Kind of out there, but possible.

But, to cover all the bases:

Do you have a dedicated WAP for your TV Receivers?

Is it located at least 3 feet from the Gateway?

Yes, the WAP is stretched as far as that little cable they provided will reach.

The ps4 never had problems, just the new 5 system is doing something to the network.

The wireless boxes and little WAP box were replaced not too long ago to try to fix this issue and everything worked fine for a few weeks. Just uploaded a new game on the PS5 ... that is when the problem came back.