That being said, when I was a dev lead, the first things I thought about when choosing a technology were the ecosystem and the how hard it would be to find competent devs. You can throw a rock and find a good enough enterprise C# dev in any major city. I would not have chosen F#.
As far as Flutter, Google has the attention span of a crack addled flea and I wouldn’t tie my horse to any platform with a Google specific language or runtime.
Even Google is moving away from Flutter for internal apps.
https://9to5google.com/2021/10/10/google-ios-apps-native/
I’m very much a native framework snob. But I understand the need to have a cross platform mobile platform for a bootstrapped company. Why not use a JavaScript based mobile platform? He already new TypeScript and Typescript devs are a dime a dozen.
Finally, why use Docker for Postgres?