Almost all mobile editors that I’ve seen just allow you put filters/text/etc over them.
I’m looking for an app that will let you have multiple layers, bring in a second image, cut out the background, resize and move it, etc.
Are there any apps like this?
Krita. It’s quite resource intensive and the UI has been ported directly from the desktop rather than being optimised for mobile, but it works, and it’s free and open source
Pretty much this, though i do hope you have a tablet.