I’d recommend learning Git entirely locally first. Git is a distributed version control system, which means that it doesn’t need a server. All of Git’s features are available to you even with just a local repo.

When you do want to have the repo on a server for your own use, you don’t actually need anything fancy like Gitlab or Gitea. Technically all you need to do is copy the repo from your computer onto the server and set up a Git server on it. That’s it. Git works over SSH, so you’d just add a “remote” that points to the server.

The best place to start with that is probably the official documentation: git-scm.com/…/Git-on-the-Server-The-Protocols

The repo on the server is not really any different to the one on your computer. All you’re doing when pushing is synchronizing them - pushing new changes from your local repo into the one on the server.

Where web UIs have an advantage is that they make it easier to browse the repo, show it to others, have pull requests and CI support.

I’d highly recommend Forgejo instead of Gitea. The Forgejo site has a list of reasons why, so I don’t go over that in detail.