After a bit more research, and help from a friend, I figured it out.
the movss and mov are opcodes and its usually in the form of a float (for movss atleast)
So, hence, you CAN change its value.
Simply write movss [..address..],(float)### replace ### with your number.
As for my question, it works, I have disabled the entire game's health decrement. ...
W System : ClassLoader referenced unknown path: /data/app/com.ibsbankmobile-1/lib/arm64
E AndroidRuntime: Process: com.ibsbankmobile, PID: 3053
The warning here shows that you have a missing path: /data/app/.../lib/arm64
This directory contains binary (compiled) libraries that belong to the app. If you repack an app, whether you changed its code or not, ...
I'm not sure about tools specifically for your first question, but as for your second question, yes, definitely!
Decompilation is useful for understanding code, but it is terrible for modifying code. Compilation and decompilation are both lossy processes. Also, there's a lot of things you can do in bytecode that have no Java equivalent, so you shouldn't ...