In my experience, most startups just want managed options they can run themselves rather than engaging partners but if that's what you need then AWS will have more companies to offer, although GCP does have qualified partners. I recommend contacting one of the GCP developer advocates either in this thread or on twitter for help, or email me separately and I'll put you in touch.
Also I havent worked with them but https://shinesolutions.com/ has put out plenty of articles and case studies that seems to show they're pretty capable, that might work for you.
For an early stage startup/Indie developer, GCP support model is not appeasing. $100 Per user for development role is unacceptable. (at least to us, the stage where we are now)
If you're very early then you can also try the older support pricing: https://cloud.google.com/support/premium/
If that's still too expensive then you can probably rely on the free support and forums until you have more spend and revenue.
https://cloud.google.com/solutions/migration-center/ is a reasonable jumping off point. Sorry if that didn't come up more clearly.