4k channels error message 721

I have a Genie 2 with 4 4k receivers and 3 regular wireless receivers and a base package of Ultimate.  I also have a Brazilian channel called Globo (ch 2134).  I had the equipment installed March 2020.  4k channels worked briefly, and then stopped.  I called multiple times and spent hours on the phone and had techs come out.  I complained on Twitter.  At one point, they actually fixed it and it worked again for about a month, and then stopped working again.  The techs claimed that there is a backdoor provision that is done by a Directv tech once the case is escalated, but that eventually when system updates are applied the error comes back.  The main reason I went with DTV was for 4k and I'm about at my wits end with it.  Billing gave me a credit that expires in September and now that I am revisiting my bill again I'm trying to fix/troubleshoot it.  Every time I see a Directv salesperson at Costco it takes all I have not to scare off his customers.  I'm about to leave DTV unless someone here can help.  I don't have the energy to call them, escalate cases, and start the process all over again.  I don't have 10+ hours over the course of the next 2 weeks to follow up on it.  Anyone have a similar experience that can help?  Any DirecTV agents out there that can help?