Debian works well for a server.

Ubuntu Server (Or really just Ubuntu) is probably going to be the easiest in terms of package support, general support, and usability. It's pretty straightforward and there's infinite tutorials for everything you could possibly want to do

Have you considered installing Proxmox? That way you can then test as many distros as possible and even play a bit with containers. I configured it recently and I'm having a lot of fun being able to take snapshots and then doing crazy things with an easy way to recover from my failed experiments.

OpenBSD.

if it's a really old laptop, Ubuntu might be overkill, spec-wise. In that case i would suggest Alpine Linux, it's super lightweight and a really good distro for server use.

Debian is the classic server choice. If you don't have any server administration experience, I'd consider it just for that reason: there should be a ton of resources available. If you want something else, any RPM-based distro (like Fedora Server, CentOS Stream, Rocky Linux, or even RHEL) could be another option, with Rocky Linux probably being the best choice out of those.

Alternatively, I'd consider NixOS or Alpine. NixOS is what I use on most of my servers, however both have attributes that might make them worse for a beginner. NixOS uses a custom programming language to configure the operating system, while Alpine is much more minimal than most other server distributions. On the off chance that you have experience with a functional language like Haskell, though, NixOS might be the best choice, since it having a unified configuration for the whole system makes it very convenient for hosting usecases.

I'd also like to note that I run both a single-user Mastodon and Lemmy instance, and find them both fairly easy to manage. There's also GoToSocial, which is specifically designed to be easy to deploy.

I’d throw an option out for Suse but if you really want as little OS as possible Arch Linux.

Plus one for Ubuntu server. Pretty easy to use and lots of community support.

My home server runs on a laptop that's running Manjaro. Does that mean I recommend Manjaro? Nope, then why do I use Manjaro? Because it's the same OS I have on my personal computer so it makes it easier to maintain two of the same than different OSs, so my suggestion would be whatever you're using on your main rig, and if you don't use Linux on it then whatever you feel more comfortable, there's not going to be a major difference between distros in their capabilities, but there is going to be a major difference in your willingness to maintain a system you're not familiar with.

I would go with the regular desktop version of Ubuntu because while laptops work just fine as personal/small-scale servers, any idiosyncracies tend to be around stuff like sleeping, power management, what happens when you close the lid etc. Whether you'll encounter any of that depends in part on the laptop make and model, but Ubuntu Desktop is probably the most polished distro out there in terms of handling those things. Edit: though maybe I'm wrong and Ubuntu Server would have better defaults around those sorts of things? Never tried running it on a laptop before.

CentOS is a good OS for servers. It also has a friendly web interface on port 9090.

Try UnRaid!

My home server is a Ubuntu install on a 2017 laptop. A lot of guides have been very useful.

I installed several other tools, with Portainer, for a variety of imaged applications. With various containers I installed Jellyfin (for hosting old videos and converted media of mine), Calibre (for a digital library of textbooks from my history degree) and a few other tools. I've been half-tempted to host some WordPress sites, but I have yet to figure out nginx...

Try running either Armbian or Linux Mint XFCE if your goal is a fast, stable, lightweight distro.