I can attest to this method being completely effective, but I think you can skip the contract work, and it might get in the way.

At least in my experience as a contractor, people are looking for contractors because they have lots of experience in this technology but don't have the resources or time to devote to their project full-time. So if you have little experience in a tech stack, you may have a hard time finding this kind of work.

I simply built a side project (I did this with Rails) and then got hired full-time at a startup to do Rails work. As with everything, YMMV.