not totally sure yet how to do that, since I’m still using 2.1, but definitely will if it’s a possibility!
Hello,
I created a fork a GB Studio 2 that export natively game in pocket file.
https://github.com/BestPig/gb-studio#analogue-pocket-export
So it should be easy to port your game without the pain of migrating to GB Studio 3.0 :)
If you have any issue with it, don't hesitate to contact me.