There's an paid app I can't find online (just old versions). I bought the app but I wanna know how to extract the app, remove DRM (license requirement) and my information so I could share the APK here.
Try to use Lucky Patcher to remove licence check, in 98% it will work. If it doesn't, well, you have to use apktool (to unpack and pack.) and jdax (to know what this smali code does. you have to understand java ofc.) also you need some kind of ide to edit smali - I personally use VSCodium.
Up of stated is for Java code that not so hard to modify. Sometimes app use DRM inside of .so files which is usually not a Java but C/C++. I that case you'll have to deal with machine code that harder to modify and even understand . IDA Pro or Ghidra can help you.