The best classes for overcoming shyness and becoming more social are called "improv comedy classes". Unfortunately, improvisational comedy works best in-person. What can you do during this pandemic?
If the core problem is you are shy then that is straightforward to fix. Just do a bunch of low risk (to yourself and others) socially scary things like giving presentations, filming YouTube videos, writing a blog, writing complimentary emails to people you respect, etc. It doesn't matter whether anyone watches or reads these things. The purpose is to decondition shyness and improve your communication skills. Eventually your brain will calibrate itself to the true low risk of social initiative. Pseudonyms are allowed.
If all you have read on this subject is Cialdini's Influences then you have not yet exhausted the trove of useful literature.
- If you want to be more social then the book to read is How to Win Friends and Influence People by Dale Carnegie.
- The basic book on negotiation for the purpose of career advancement is What Color Is Your Parachute?
- My favorite book which puts all three topics together is Built, not Born by Tom Golisano.
I also like to ask for occasional mentorship from a senior engineer I trust and respect, but this option is not available to everyone.