GitLab team member here.

Next to using GitLab.com SaaS, Open Source Program members can also choose to self-manage their GitLab instance -- like Arch Linux.

> The drawback is that it looks like you have to apply for it to use it.

This is a requirement, yes, but should not take too much of your time. You can learn how the process works in https://handbook.gitlab.com/handbook/marketing/developer-rel...