What is the status code of that page? Is it actually an empty response, or does it just look blank in a browser?

When you access it from the internet, do you use an ip and port or a domain name? My first guess is that you entered the domain name somewhere in the config of either Opencloud or a reverse proxy, and the mismatch (between the expected domain name and the ip address used instead) is what causes trouble.

because /etc/hostname is allowed to contain only ASCII Latin characters, numbers, and dash

If you really wanna go for cursed, the syscall to change hostname doesnt have this restriction, and I do have a working system with non-ascii characters in the hostname. It takes some fighting with systemd and NetworkManager, and stuff does sometimes break, but it can be done.

I recommend the free tier of healthchecks.io for this. I have all of my in-depth monitoring selfhosted, but use this as a general "is it at least online" check that tells me on multiple platforms if it isnt.

This explains systemd versioning so well.

F12 just opens the developer tools as a whole, but there are also shortcuts to jump right to specific tabs (like the console or debugger, not just the inspector).

That was not scheduled maintainance, that was theit WaF and Workers dying. https://www.cloudflarestatus.com/incidents/lfrm31y6sw9q https://www.cloudflarestatus.com/incidents/k9ppxftx8bs5

I found it in the settings:

Under "Features":

It does (not sure how well), but it seems to be a paid feature. Found under Settings -> Split tunneling.

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.

Just buy 1674920 more of them, way easier.