I face this problem quite a bit myself - the moon ends up tiny on the screen even with zoom. The A54 has a solid camera, but you need some tricks: use Night Mode or Astrophotography mode if you have it (some Samsungs do), prop your phone firmly on a tripod or lean it against something stable, and activate 3x optical zoom before you shoot (don't use digital zoom after, it tanks the quality). It might sound obvious, but most people move way too much while taking the photo - the moon really demands a steady hand.
Apps like Snapseed or Lightroom Mobile help tons afterward to recover details and bump up contrast, because the photo comes out kind of blurry either way, but you can save it in editing. If you want something more specialized for astrophotography, there's Astrophotography Tool, but honestly with Samsung's native settings you can already get a decent result.