It seems a little easier to go from embedded to app dev than vice versa, harder still to think up a personal project involving embedded to get you excited enough to invest the time into learning by hands-on trial and error.

I’d be interested in some started points, books, etc. to embedded, even beginner ELI5 fun projects. I am familiar to RPis, ESPs and similar microcontrollers for fun, but curious about what career and industry practices are common and different compared to app dev.