The best source for learning Google is Google. 

Try out the training for Google Certification: These tutorials demonstrate a skill and offer quizzes so you can show how smart you are.  Click on Get Started to begin. And then consider taking the  Certification exam.

Google Educator's Learning Resources:  Tutorials for all G Suite tools and how you can use them.

Google Workspace Learning Center:  More general (non-educational focused) tutorials and training for all Google apps

But Google isn't the only source.

Eric Curts: Eric's web site CTRL+ALT+Achieve is an excellent and thoughtful resource. He regularly shares Google tool ideas and creativity.

Kasey Bell: Kasey's Shake Up Learning shares resources around teaching , but also offers courses and more at her site. (Fun fact about Kasey . . . she's been to Ehlenbach's Cheese Shop.)