I think the Archinstall script (that is part of the official Arch iso) can save the configuration, to reinstall with same setup again. But it does not go into details like your Firefox environment. Its there to setup the basic installation and eventually additional packages.

Their are a load of ways to do this. I have seen some good once posted already like Ansible. But to give you some more options. Their is also imaging. You setup a system how you like and clone it essentially. A good tool for that is a fog server. Works cross platform too.

The canonical method was with a kickstart, and if it looks like too complex, remember you should have one stashed in /root already that you just need to mod.

Normally a kickstart is a bit much, otherwise, though. I use a suite of tools but the best one I used was a simple virtual package to bring in the ot8her, drop configs in and start daemons. We did this in like 2001 to great effect.

You should have a look at NixOS. It’s a Linux distro where you declare the whole system in configuration like files, in a language called Nix (hence NixOS), then you run a command and that gets resolved into your system.

It takes a long time to setup the first time, but it’s a breeze when you need to reinstall, and you will never need to reinstall as every boot is a fresh copy of the system you declared.

There’s also a thing called home-manager which uses the Nix language to declare your home configuration. That part can be used in any other Linux by installing the home-manager package.

You can declare your OS in a way that the home part is portable for machines running other systems. I do that, then my machines are very easy to declare, and with some groups for things like Base (Terminal, prompt, some things I expect to have on every system like Python, nvim fully configured, etc), Gaming (Steam mostly), UI (Sway, many GUI things I use like browser with extensions, etc) I can add configs for a new machine in instants depending on what I expected for it, and if I ever want to convert my “Steam machine” into a desktop it’s just a couple line changes, regenerate the config and it’s exactly the same as my laptop.

Honestly I don’t think Nix is for everyone, but it’s a very niche thing that works extremely well for what it sets up to do, and if you’re in the target audience it’s a game changer.

Fedora offers kickstart.

Others have cloudinit or ignition.

Those are the ones if used personally.

If a debian based distro there’s several ways to copy your package choices from one machine to another, the likes of using dpkg --get-selections and using that output on the new machine with --set-selections, but probably the easiest way is to use apt-clone, which streamlines that process to install the same packages on the new machine.

As for your firefox and desktop packages, they’ll be saved in /home/username (usually in .hidden dirs) - so just copy all of that over.

Alternatively, use an image cloner like clonezilla to make an exact disk copy and install that.

Or run your machine as a vm inside Proxmox or another hypervisor. That way you can have instant snapshots before you do risky things, as well as multiple scheduled entire-machine backups.

Or ansible (which I do a lot of), which can set whatever packages and copy your golden-image files over as you want. (But keeping those up to date requires a little thought)

Ansible, Salt, Puppet, Chef, Terraform, …

I frequently reinstall Linux.

Like, how many times in a year? And secondly, for what reason?

The best would be NixOS, but if you just want to automate your install which you have then Ansible.