If you only need a bare minimum, and don't plan to heavily use CI/CD, container/packages registries, integrations with other tools i would go with gitea/forgejo (you can always use external tools on top), else i would use selfhosted Gitlab, it has pretty much all the things you could imagine to need with software development and deployment
+1 for Gitlab. As the number of developers increases the features of Gitlab will get more and more important. Only OP can say, but if they're closer to 9 developers than 2, I think it's a safe bet they'll need the extra features sooner rather than later.