Intermediate/advanced MERN/PERN programmer tutorials

I’m a full stack developer that works on the PERN stack. My experiences at work are mostly with monoliths (not that I have a problem with monoliths) and using sort of home grown patterns as opposed to industry best practices. We also don’t do any testing which I’d love to see in a production environment. I was wondering if anyone had any suggestions for tutorials that show what modern MERN/PERN stack development looks like - instead of a ‘from the ground up’ sort of approach, so I can start trying to copy patterns from more experienced devs in the field while building some cool projects and learning new stuff at the same time.