Go's historic maintainability strong suit has been its simplicity and consistency. The syntax is, relatively speaking, lightweight, the language invites complexity through composition, and information density for any unit of code is typically quite low (which isn't necessarily a bad thing).
In my opinion, though, these are all drawbacks, and Rust addresses all of them. It's syntactically and semantically much heavier, leading to its oft-maligned steep learning curve. It has, uniquely among the major languages, I think, a syntax for expressing variable lifetimes (with its own unintuitive semantics). It stuffs lots of abstraction into a hodgepodge of terse semantics and punctuation.
It sucks to read, until you get really used to it. Then it tends to read really quickly, and, at least for me, it's easier to reason about a conceptually-broad piece of logic if I don't have to jump between different locations in a file, a module, or a package to do it.
With Go, I find it more difficult to get into a flow state, and easier for my eyes to glaze over when looking over large diffs.
It's not lost on me that these are purely subjective arguments, though. My preference remains with Rust, and that goes back to before I used LLMs.
I'm also aware that Go is very prescriptive about how you write it; it's explicitly opinionated, and Rust doesn't have that. It means that most Go code bases will look more alike. I consider this an anti-feature; I believe code should be able to conform to the problem space or product and a good team will find the best way to do that.