Here are great resources and free training programs for aspiring Bitcoin and Lightning developers. Qala is a program specially designed for developers in Africa. The program is full-time and includes stipends for participants. Apply now: https://qala.dev
Summer of Bitcoin 2022 is a program for developers and designers with great mentors. Apply now: https://www.summerofbitcoin.org/
Here are the learning resources by Chaincode Labs. They are running residencies too.