Importing a specific commit of go subdirectory module with same module path as root

I am given a repository hosted on a private site, and it looks like this:

a-private-git.com/myrepo/
    go/
        go.mod
        go.sum
        bar.go

The repository is located at a-private-git.com/myrepo and the module file is: (Note that the module itself is actually located at a-private-git.com/myrepo/go)

module a-private-git.com/myrepo

Is it possible to include a specific commit/branch of this repository? Or do I need the provider of the repo to change it?

I've tried:

go get a-private-git.com/myrepo@v0.0.0-<commit time>-<commit hash>
> the module is added to go.mod, but when I build I get:
> no required module provides package a-private-git.com/myrepo; to add it: 
>    go get a-private-git.com/myrepo

go get a-private-git.com/myrepo/go@v0.0.0-<commit time>-<commit hash>
> module declares its path as: a-private-git.com/myrepo
>     but was required as: a-private-git.com/myrepo/go

(Based on https://go.dev/doc/modules/managing-source)
go get a-private-git.com/myrepo/go@go/v0.0.0-<commit time>-<commit hash>
> invalid version: unknown revision go/v0.0.0-<commit time>-<commit hash>

The easieset way would be to simply 'go get' the commit hash you want:

go get a-private-git.com/myrepo@commit_hash

Alternatively you can use a branch name to get its latest commit:

go get a-private-git.com/myrepo@branch_name