One nitpick on the transfer. DO offers 5TB which at $.12/GB on GCP would be $600 worth of transfer not $8. If you need lots of egress DO wins hands down.
Realistically few are going to need the full 1TB and most will be closer to 2-10% on average (my guess from hosting industry experience).
In my professional work all of this is someone else's job, but I've experimented with Google Cloud Platform, Amazon Web Services, and Digital Ocean, and only with Digital Ocean did I feel confident I wasn't going to make some kind of costly mistake.
Every time I have to update something on GCP App Engine, I end up creating a billing account so I can use Cloud Build for a Node.js app, then blow the billing account away after the app is deployed. It scares me to create a way to be billed when everything I'm doing is at the free-tier level.
On AWS I discarded my account entirely after I got a bill for a few cents when I wasn't (knowingly) using anything at all.
AWS charges you for storage, so even if everything is turned off you might have an old snapshot hidden somewhere racking up a few cents a month.
I've found AWS billing to be annoyingly opaque when you're trying to figure out what a service will cost you next month. I guess people who use it a lot have a system, but as a small fry newcomer they seemed really shy about what stuff cost.
Realistically few are going to need the full 1TB and most will be closer to 2-10% on average (my guess from hosting industry experience).