I'd love to test 26.1 but I don't want to install another beta at the moment, especially this early in case they push out updates fixing things. But hopefully 26.1 does fix the issues.
I'm amazed that this was never caught during 17 testing. Surely they had some people doing real-world tests and actually used wireless CarPlay, especially with all the Ultra CarPlay stuff they've been working on. Knowing Apple, they probably tested it on one model that the 17 PM just happened to like and thought, “Yeah, works great.” 😄