How to remove "Course starts in X months" reminder from pre-release courses

I have a beta testing site where students are enrolled as beta users specifically before the course gets moved to the production site. However, there’s a little notice at the top of pages that says:

 **Course starts in 2 months on Sep 29, 2022.**
Don’t forget to add a calendar reminder!"

That confuses some beta testers into thinking that the beta testing hasn’t started yet, and then they don’t start the class on time. How can I remove that notice? (Or perhaps how can I alter what it says so that it instead says “The beta will end on Sept 29 2022”? That string seems to be here, but is there a way to alter that besides forking edx-platform?)

And for that matter, is there a way to remove the “Dates” pseudo-tab at the top? (I can’t hide it with the eye-cancel the way I can the wiki on the Pages tab…)