I’m in a similar situation as a backend tech lead at a FAANG-like company but I also have a side project web app that generates about $500/month from ad revenue. I find that I learn a lot from the side project that helps me at my day job like front end development, ux, listening to user feedback, deployment all the way out to end users, and programming in other backend languages I wouldn’t have an excuse to play with at work.

Also the higher up I move on the engineering ladder at a bigger tech company, the more valuable it is to spend time doing things that aren’t coding. The side project lets me scratch my coding itch while doing the more valuable stuff all day.

Edit: typo