Let’s start with a general guideline for programming Go: write Go programs by writing code, not by defining types. When it comes to generics, if you start writing your program by defining type parameter constraints, you are probably on the wrong path. Start by writing functions. It’s easy to add type parameters later when it’s clear that they will be useful.
This is about generics, but the advice applies. Write your Go programs by writing code. When it comes time to optimize, you can focus on the specific parts of your program that are slow or using up too much memory. In my experience, as long as you’re writing sane code, memory allocation and garbage collection in Go is mostly a non-issue. I’ve had to dig into the garbage collector in my .NET days, but have yet to with Go because it is efficient and basically Just Works™.
What will you speed up using concurrency and how/why? Concurrency inherently adds overhead (though it’s less of an issue in Go due to goroutines) and I’ve seen people fall into the pitfall of just assuming it will speed things up. That said, this book is a good place to start.
Anyway, in summary: just write code in as idiomatic way as possible (which is easy in Go because it’s opinionated) and I bet your binaries will be plenty fast and barely sip memory (that has been my experience at least!). In the real world, 99 out of 100 times, my performance issues are from another layer (an external API I rely on, slow database queries, etc.). When a specific performance concern comes up, solve it with a specific solution.
As you are new to Golang, the first step you should do is to learn the syntax, if possible perfectly. Then the second step is to write as much code as you can, just to practice it. The third step is to write as many small applications, of diverse types, using Golang and additional libraries. The fourth step is to write as many medium size applications, to study various architectures in Golang.
After you have done these 4 steps (at best several months from now, if not years) then you can realistically start worrying about optimizations. I am not trying to lower your enthusiams, but you need to first do the ground work.