It feels like you did not read that post. It's in the Known Issues category and persists as a holding place for a Known Issue that has not been solved yet. Everything you just asked in this comment is addressed in that post.
We had it mostly solved and, with tvOS 17, Apple pulled the rug out from under us. As is mentioned in the topic I linked to, this is not anything third party developers have direct access to nor documentation for from Apple. Like many Apple technologies, it's just a black box that either works, or doesn't. I'd prefer to not repeat everything else listed in that post.
I understand that it's disappointing to you, and I can assure you that it's disappointing to us. At this point all we can do is be as transparent as we can about it. Most developers would just be radio silent about a deficiency like this and ignore every single inquiry about it.
If this is a deal breaker for you, then I would completely understand if you reconsidered the use of Channels completely. Every product has pros and cons and it's up to ourselves to make buying decisions based on how those pros and cons effect ourselves and our use of the product.