how do i remove a screentime password that’s forgotten

If you can't remember a restrictions passcode that you set on a previous version of iOS, or you forgot your Screen Time passcode, then you need to erase your device, then set it up as a new device to ➔How to remove the passcode. Restoring your device from a backup won't remove your passcode UNLESS your backup was created BEFORE the screen time passcode was created.

If you have updated to 15.x then follow these instructions ➔ If you forgot your Screen Time passcode - Apple Support

Axel F.