Not a bad plan, it is a drawback of Godot that you sometimes have to 'make' things work.
I'm getting to the stage with my own dev skills that I can build my own systems, nodes and classes in the Godot engine, and have even extended the engine once or twice simple ways to expedite some parts of my projects.
I wouldn't call myself an expert developer or programmer, ir even an expert in Godot, but each jam and each project helps me improve.
Either route is beneficial and we always can switch to something else. At the end of a day it is not about the engine, so whatever gets the work done.
Yes, jams are quite helpful to understand the scope and how to finish something workable under a deadline. Pet projects can last decades otherwise, if not careful.
Being an expert is not crucial, as long as you can produce something. Unless your goal is to be the expert, not to make games (I mean goal to be hired for the expertise, compared to going indie).
