Ask HN: Basic cryptography course for average developers?

When I was working with JWT, I realized I have no idea about the difference between different types of algorithms: RSASHA, ECDSSHA, RSAPSS,... What are they used for and when to use what? Why different algorithms require different types of public/private keys, what is a PEM file, what is a certificate...?

I understand hashing, signing, how public/private keys work in general, but that's about it. So I'm looking for resources where I could learn more about this and to discover the unknown unknowns area of my cryptographic knowledge.

Some of the resource online I found (mostly blog posts) usually cover only 1 topic or sometime very shallow. I'm looking for something organized, good coverage, and practical. Definitely not planning to become an expert or anywhere near it, just enough for an average developer's daily works.

If you have any suggestions, online courses, books, lecture videos... please let me know, I don't mind paying for quality contents. Thank you very much!