Docker and Podman are both free. Podman is the lighter weight, more FOSS, also slightly more DIY option, they are intercompatible - I work on systems for spacecraft and Podman is what we use on those because it’s lighter weight. If you want to run something in docker, ChatGPT is actually pretty good at talking you through the specific setup (at least that’s been my experience).

Docker and podman aren’t too bad nowadays I don’t think assuming you’re not running something huge

(Podman is another tool that does the same thing as docker)

Docker and podman containers are basically like throwaway mini-vms that contain one application to ensure it will always run no matter where so long as the machine you’re running them on can run docker

They can run CLI stuff just fine, I’m not sure about desktop apps someone smarter than me will probably tell you about that

FOSS lightweight ”virtual machine” (it’s not quite a VM but it’s similar conceptually. It’s much lighter on your system than a VM).

Easy to install, setting it up for your use case may take some coding if it isn’t common (bash scripting experience will help).