iPhone 16 Pro Max starts beeping while charging

I bought a IPhone 16 Pro Max for myself over the holidays. For whatever reason my phone & year old IPad have started beeping while charging. Like the plug is not making a good connection or something? The brick & the cable are both Apple approved but even at that there is no darn reason…it’s making me nuts! How do I make it stop?

Thanks much

[Re-Titled by Moderator]