Getting 4K TV from Xfinity

I just had the most laughable chat session with Xfinity. My question was, if we get the Xfinity TV package with 125 channels, which channels can we receive in 4K/UHD even if a "special" box is required? The lack of ability of 5 agents to answer the question was ridiculous. I was fully expecting the answer to be NONE of the channels in the 125 channel lineup are 4K because Xfinity TV service is HD/1080p at best/most. I didn't even mention streamed services through Xfinity. My wife is used to using a DVR and is annoyed by constantly logging-in to one streaming service, then having to switch to a different streaming service for a different show. She'd rather have everything "integrated" into the DVR experience. Is there anybody reading this who can speak to whether there is any Xfinity DVR-optional TV service they have that also delivers (and records/plays) programs in 4K? I have accumulated a ridiculous number of 4K TVs and am annoyed with the lack of 4K options from the satellite companies (yeah, they are maxed-out on bandwidth and can't deliver any more 4K content without building new satellites and launching them... an incredibly expensive process). Since 4K/UHD is 10 years old now, you'd think Xfinity would have had time to get some 4K channels working, but it wouldn't surprise me if Xfinity was not keeping up tech. Their internet service (at least around here) is incredibly good in terms of speed, cost, and reliability/lack of downtime. But they are CLUELESS on the TV side of their house. We are also considering moving our 2 cell phones to Xfinity to get bundle discounts that look like they can save us more than $100 a month on cell phone/TV/internet, but I can't get any straight answers out of Xfinity about what speeds are supported on T-Mobile's 5G network at the prices Xfinity advertises. The TV service chat people kept talking in circles to the point I'd ask if they knew what 4K was. When I did that, typically, the agent would disconnect from me without announcing what they were doing. The chat would pass to another agent who claimed to read the first chat session, then proceed to ask the same questions that caused me to ask the previous agent if they knew what 4K was. It was amusing and sad at the same time.