I’m personally using LMMS (Linux MultiMedia Studio) which despite its name, also runs on Windows.
It is free, it is open-source, and it’s available on the biggest linux distros. It has a lot of capabilities, although depending on tools you’ve used in the past, it might have a learning curve. There are plenty of tutorials online.
Keep in mind this is a tool that one would need to spend time learning, and not one that you can learn in 5 minutes. Depending on your knowledge in audio and music theory, it might get easier/harder to get used to.