On 4/19/25, I have submitted a Bug Report for this issue per the suggestion of another user. Like so many, I do not like the feature of having to have CarPlay on 100% of the time in order to get the banner and the alert notification sound or else you usually just get the sound but no way telling who was sending you a Message, as Corys26 pointed out here in Discussions, that this is a design change and unless many complain about it, I'm sure it will remain as is.
Now, fast-forward from there, this other issue, the one that I composed this post for, is still ongoing. I did recently update to iOS 18.4.1 and there was a note RE: CarPlay. Whatever that was, did not resolve this. The issue still remains that there are no notification sounds that many, in more recent updates, have also experienced and complained about. The most annoying is Siri no longer giving play-by-play directions in Maps for navigation purposes. In my opinion, this issue has become worse than better.
I am waiting to hear back from Apple Support about this.
Thanks.