I think the Apple App Store mostly sorts by popularity and they use reviews, some mixture of the quantity and star rating, to decide that popularity amount.
Anyway, ignoring the obnoxious Apple-inserted banner ad (🙄) typing in “lemmy” or “memmy” bring up the correct app for me now. I had the .ipa sideloaded previously, but yesterday typing in lemmy brought up some other completely unrelated (not lemmy) app came up and memmy I think didn’t work at all. Seems ok now though since most people will go to the App Store and type lemmy.