Thank you Tesserax! I've seen this question asked before on this forum and it's often misunderstood as "How to cancel AppleNews+, or something like that." Others have suggested choosing Preferences -> "Restrict Stories in Today" but that only restricts stories to news channels you're subscribed to regardless of whether they are News+ or not. So if for example you're subscribed to the Newsweek channel and Newsweek offers a story on News+ you still see the headline.
Not the answer I wanted but it is the Correct Answer: "Readers of Apple News are stuck with seeing AppleNews+ headlines" and there is nothing to be done about it.
Thanks again!