MacBook Pro screen dimmed whenever I wake it up

If on battery power, then you need to uncheck "Slightly dim display when on battery":

Change Battery settings on a Mac laptop - Apple Support

Try clearing the NVRAM by using the following command in the Terminal app:

sudo  nvram  -c

This command will prompt you for your admin password. Nothing will appear on the screen as you type the password. Press the "Return" key to submit the password. You may see an error related to the Computer Name (perhaps several errors related to the computer name). As long as the command otherwise completes successfully, you need to restart the computer so the system pulls the default values from NVRAM. After rebooting, you will need to re-select the default Startup Disk in System Settings.

Make sure that you are not blocking the top center of the Display Assembly around the camera since there is an Ambient Light Sensor located next to the camera which can affect screen brightness.

Consider toggling the selection to see if desired effect

may take, after doing so. 🌼.A restart might help.🐝