Codeberg is a public non-profit Forgejo instance hosted by the actual maintainers of the tool. They’re compromised with free software and provide their services with no pay walls other than a single limitaiton: only accepting open-source projects in their instance. That shouldn’t be a problem if you want to work on open-source, right?
You can just downlaod any linux iso, e.g. fedora fedoraproject.org/workstation/download , and install it in a virtual machine. This way you can play with linux.
You can also write it to an USB and boot from the USB, nothing grts written on any other storagr device and you can test if everything works, check for compatibility, play around and once you’re done, you shut down, remove the USB and your PC is like nothing has happened. Getting to know how to download an iso, write it to usb and boot from it is a common and easy task.
I’ve never heard of a common video format not playing on linux