Most folks I know do 20-35 of real work (including meetings). It's salaried though, so you can go through spurts of much higher work or just straight up coasting. Highly team dependent.
First world problems: you got a job at Google, millions aspire to be there but don't get the opportunity and here you are worried about WLB and the flavour of coffee in the coffee machine
I typically am in the office from 7-8 hrs/day, and usually don't spend more than a few minutes working in the evening. L6 SWE.
Most of the staff/Sr staff SWE that I have seen work 60-70 hours per week.
Thats what I figure. So are those other replies liars? Honestly, i don't know anybody in tech that works less than 45 hours a week, typically it is 50.
Depends on your productivity, your team, your tasks, your drive to get promoted. Most L5 don't expect to ever be promoted again so they can coast more readily than lower levels. Also staff/sr staff tend to work more and are not senior devs as you originally asked
Im not at Google but an Alphabet co. Most weeks about 40. Crunch time can be 60 or more