I noticed on low settings with HEVC on my 3A, photos still take 4-12 MB because it's storing at 4000 pixels across (12 MP main) or even 6000 on the selfie cam:

Which doesn't really add that much clarity when zooming in, and is also impossible to see on the 1080p display.
I ran some simple commands to resize all my photos with ffmpeg to 2160 maximum on either side, and it makes practically zero difference in quality when zoomed in, but the file size is regularly 300-500 KB.
Now I'm pretty sure most people do care about their image quality enough that they won't do this, but I want to save on storage when it's not necessary to store redundant data.
So can someone suggest a camera app where I can fine tune the quality output?