I guess Settings App -> System -> Feedback. But i think this is an OS feature request (like Jet in the other comment said), which is being handled by the manufacturer of the device you’re using instead of the actual AOSP. I’m not sure where you can leave feedback for AOSP, if that’s possible at all. Hope someone else can add that here.

The process for submitting feature requests is here: https://source.android.com/docs/setup/contribute/report-bugs

Also, apps on modern Android are mostly sandboxed so they wouldn’t be able to “block” your phone on their own unfortunately. You could have one that You make/install that could do “things” but you’d be really limited without root access to your phone.

As for the phone locking when you plug it, you can make an app that detects when the phone is being charged. What I don’t remember is if you can force-lock your phone from user space Android-provided APIs. Keeping it on while plugged is possible by checking the appropriate checkbox in the developer settings “keep screen on when plugged”.