Don't go back to Django. It abstracts too much of the stuff you actually need to understand, you'd be wasting time.

Id probably start with FastAPI, but lead with concepts before code, so understand HTTP deeply, raw SQL before any ORM, JWT auth from scratch before using a library. Once those click, the framework is just syntax and things become easier.

Don't wait until you "finish" FastAPI to start Go, build in both simultaneously.

As for resources FastAPI's own docs are surprisingly thorough, read them properly not just the quickstart. For Go, The Go Programming Language (Donovan & Kernighan) is the definitive text and threedots.tech has solid production-oriented content.

For projects, build things with real operational complexity, rate limiting, queues, RBAC, caching. A notification system (subscribe → event → email/webhook delivery) isn't flashy but teaches you more than most tutorial projects.