Jadx is also available as Java library. In your own program you are free to develop a cli or UI interface as you want and decompile methods on demand.

https://github.com/skylot/jadx/wiki/Use-jadx-as-a-library

You will require to write a pretty big chunk of code to archive that.
In short, you can iterate all methods and get method code with MethodNode.getCodeStr, next search your string in that code, if found, get all use places of that method with MethodNode.getUseIn and build desired trace.
To integrate with jadx you can use:

• jadx scripting - wiki page
• jadx plugin - wiki page
• use jadx as a library - wiki page

Wow..so hard
Maybe it will be good idea to export API using Python