Apple is giving you
extra pixels, not taking any away.
If you want the same appearance (and resolution) as a non-notch MacBook Pro, open System Settings, go to the Displays section, click Advanced... and toggle on “Show resolutions as list”, save that change, and then enable “Show all resolutions”.
Now select the resolution option just below your current selection. (The y-dimension will be slightly less, which equals the space added by the pixels around the notch.)