I actually wanted to get the notch back so I could have as much vertical screen real estate as possible and was disappointed to find that there doesn't appear to be any reliable way of doing this.
The notch is definitely still there by default.
Currently it's set to 1710 x 1107, which is labeled "Default", and no notch. When I look closely at the right angle I can clearly see the notch dipping into the screen, but the OS does not use any of the area to either side of the notch--it's completely dark there.
Just now I ticked "Show all resolutions" and tried at least a dozen other available resolutions and none of them use the screen above the notch bottom. Sonoma 14.6.1, 15" M3 Air.
One thing that did occur to me though is that it was a 'refurbished' MacBook. Bought it from Apple, and it looked brand new, but it does seem possible that someone could have done who-knows-what to it before I got it. Or perhaps there is some defect in the display near the top and Apple did this intentionally to conceal it.
This review says it beats M3 by 2 hours: https://www.tomshardware.com/laptops/dell-xps-13-9350-review