I'm currently an engineering manager at Google (in the US, though not in the Bay Area), and I'm sympathetic to everything you've written here; I've done my time in Larry and Sergei's Protobuf Moving Company. Being in my 40's (fairly old for tech!), if I were in your position, I'd try to find my Sustaining Passion outside of my day-to-day work. That might mean picking a 20% project that excites you, or it might mean finding something meaningful outside of the company that doesn't require a new job. It might also mean finding a new team within Google, or even a new role (e.g., move to SRE, TSE, DPE, etc). With one promotion in 6 years, I'm assuming you're hitting CME/EE every cycle -- which is good -- so I'd position that as a good thing: for many roles, consistency and stability are a feature.