My backend setup for my one-person startup ("case study" for my book, https://opinionatedlaunch.com) is GitHub (for code repo and CI/CD), Firebase (auth, analytics, push notif) and CloudFlare (static pages, DNS stuff) and Fly.io. Less work but more done.
My only complaint Fly.io doesn't have managed DB (https://fly.io/docs/postgres/getting-started/what-you-should...) and task queue.
At work we use GCP, but try to be as high as possible in the abstraction layer (e.g. use Cloud Run and Cloud SQL).