Go with Bazel gives you a couple options:
* You can use gazelle to auto-generate Bazel rules across many modules - I think the most up to date usage guide is https://github.com/bazel-contrib/rules_go/blob/master/docs/g....
* In addition, you can make your life a lot easier by just making the whole repo a single Go module. Having done the alternate path - trying to keep go.mod and Bazel build files in sync - I would definitely recommend only one module per repo unless you have a very high pain tolerance or actually need to be able to import pieces of the repo with standard Go tooling.
> a beefy VM to host CI
Unless you really need to self-host, Github Actions or GCP Cloud Build can be set up to reference a shared Bazel cache server, which lets builds be quite snappy since it doesn't have to rebuild any leaves that haven't changed.