Zoom enhance not only increases the resolution of a picture it also zoomes in the picture making it neat. The feature requires powerful hardware and according to the article only available on Pixel 8 Pro, Pixel 9 Pro, 9 Pro XL, and 9 Pro Fold.
Pixel 9, Pixel 8, Pixel 8a are not included. So, if you care about this picture do not get these pixels.
A good alternative if you just want to enhance the resolution of a picture is SuperImage on Playstore. There's a version on fdroid but it's outdated.