You can change default sorting in Lemmy settings, but i agree that constant refreshing is frustrating :(
Try Mlem! It's still in Testflight (beta version for iOS), but you can create testflight account and download it for free. It will also help creators of the app find bugs and whatnot! I'm using it rn and it's nice, they're very passionate about it! if not mlem you can also open Lemmy on safari and then make webapp by tapping share icon and then choosing "add to home screen". It will create bookmark on home screen that dont have browser interface and it's working really good actually.
That were first two days here, but now I'm invested, people started to share more and suddenly i catch myself scrolling Lemmy for 15 minutes instead of working