You’ve seen how simple it is to create a RESTful API with only a few lines of code. Huge frameworks are not needed, especially if they have their own philosophy which does not match to the standard concepts of Go.
You can create a RESTful API which matches your own requirements. It does not has to fulfill the requirements of other users and is absolute focussed on your needs. Additionally, it is easy to extend it to your needs and it is free.
As you write - and hopefully comment and document - your own code you can always maintain it. That’s not only meant to fix bugs as fast as possible, but also to make it easier to understand and to extend it.
Once spending some time on understanding the idea of RESTful APIs, you get a better list of your requirements but also what you don’t need. This way its more simple for you to evaluate different existing solutions and compare them. So you’ll find the best solutions for your goals.