The really simple setup for a single user is just a SSH server with access to storage and the git command. Assuming your laptop and desktop have SSH access to server, you can just:

ssh server git init --bare somerepo
cd somerepo
git remote add server server:somerepo
git push --set-upstream somerepo master #(or main)

and then git clone server:somerepo.

For something slightly higher-tech, I recommend going with Forgejo (the fork of Gitea). It is really easy to set up and low maintainance.

Avoid GitLab for small setups, it is fairly resource hungry.

I would guess real person. Posts without images just get very little traffic, so I assume thats why people are starting to post this.

Well, fortunately it still works. Also, it seems like the forked version did not stop development.

I recently migrated from Element to Element X with first the proxy and now simplified sliding sync, and it feels way faster. Imho Element X is still very alpha software, so I wouldnt recommend it to the general population just yet (and I still occasionally have to open the old Element), but the speed is really noticeable on even a very small instance.

Sliding sync was recently implemented in Synapse itself, so as long as your Synapse is up to date there shouldnt be any more setup on the matrix side. Try checking the Synapse logs for any issues and/or the cloudflare tunnel configuration (I have no idea about what it does to traffic).

I see why automatically giving them out (like in ACME) would be a bad idea, but other than that, why not? Even https://1.1.1.1 has a DigiCert cert.

There are more reasons, as LetsEncrypt might be more restrictive on what you can get (for example, you cant get a certificate for an IP address from them). But, as 99.99% of usecases do not require anything like that, go with letsencrypt until you know of a reason not to.