[corethree]

You don't need support. Monad composition isn't a special feature it can be implemented directly.

Not an expert in Go but I think you can do this:

   func compose[A any, B any, C any](a func(A) (B, error), b func(B) (C, error)) func(A) (C, error) {
      return func(aInp A) (C, error) {
        res, err := a(aInp)
        if err == nil {
           return b(res)
        } else {
           return *new(C), err
        }
      }
   }

The above is equivalent to haskells fish operator >=>

The bind operator (>>=) can be implimented in terms of composition:

   func bind[A any, B any, C any](a func(A) (B, error), b func(B) (C, error), aInput A) (C, error) {
      return compose[A, B, C](a, b)(aInput)
   }