TL:DR - In September of 2023, it works. It's awesome.
Just a note because I couldn't find anything similar out there -- After fighting IPTV buffering issues at a recent house party (with a 1 GB connection), I finally surrendered and picked up a cable card from the local Astound (formerly Wave) office (and a ~$110/month subscription). The lady at the counter found one in the back and, though she seemed to be pretty experienced, had never actually sold one. She had immediate access to some manager who walked her through the process.
I ordered an HDHomeRun Prime and it arrived a couple days later. That's when the adventure started. Even when the card is registered in Astound's system to your account and attached to a cable subscription, the device still needs to be "validated." I called in a couple times and the people I talked to literally had no idea what I was talking about. One offering to send out a tech because "THERE'S NOTHING WE CAN DO ON OUR END," which I assured her wasn't true. The second literally hung up on me (I'm transferring you to a department that can help). The third was a guy who figured out that there are two methods to validate the card -- evidently, if you have a TIVO there's an automated process they can use to validate the card through the TIVO menu. However, if you have a device like the HDHR, they have to do it manually. And, yes, they can do it. They just need to take your Cable Card ID, your Host ID, and your Data number. No tech visit needed.
I let the guy go as soon as I saw it said "Validated," however, I soon learned that I couldn't find any channels but for the SD and HD versions of the Outdoor Channel. Weird! I called back and the fourth person I talked to literally pulled the "I'm transferring you to a department that can help" trick at exactly 8:30 pm which is when they close. And, of course, it hung up on me.
I called in a couple times this morning and the first person said there was nothing she could do and offered to send out a tech, which I said would be fine. Of course, all the techs were fully booked, so the local dispatch office would have to call me.
I decided to call in again and I got a gal who suggested there might be a couple things she could do. She first ran a "reset" (I think that's what it was called), but then she ran a "balancing and initializing hit." And when I scanned channels started showing up! But then they all disappeared again! And she said there was nothing she could do, so I told her there should already be somebody calling me to schedule a tech visit.
Then, in a final last desperate try, I called in again. Every time you call in for "Technical Support," followed by "Cable TV," they begin the call (prior to transferring you to a human) by sending another reset signal and sure as shit, ALL THE CHANNELS FINALLY SHOWED UP! Rad! They've been rock solid all day long. I'll update this post if that changes.
I got the basic and extended cable packages from Astound, which includes nearly all of the sports channels EXCEPT for NFL Network, Redzone, MLB, ACC Network, and SEC Network. None of my channels are behind DRM. It all works beautifully with Channels. Of course, I can't speak to the premium channels.
Hope that helps people. I can't say I recommend the process, but I'm stoked to be using Channels with rock-solid cable feeds (in a container on my Unraid server working my GPU). Sure wish they'd make it easier. At one time I was thinking I might order another cable card so I can have a total of six tuners available, but there's no way I'm going through all that again. Nevertheless, I'm really grateful that Astound still offers the cards and lets people like me plug them into HDHRs. Channels is a wonderful software suite, and with the fantastic EPG support for HDHRs it's really the most premium live TV experience available.
** edit - I should also offer that Astound offers excellent TVE support. So long as they don't change anything, I'll carry this sub indefinitely. They charge a ton, and in my experience they don't even really try to sell their cable packages (they're not going to work you with promotions), but at least they offer a premium product.