Not FOSS, but Renoise is phenomenal and works on Linux, at least. Made by a very small company. Difficult to get used to if you’re not familiar with trackers, but not that difficult. It’s not Ableton Live, but it’s way up there in terms of professionalism and flexibility. And it’s very cheap, too.
You mean Steev Mike. I swear this conspiracy was about 20 years ago now; there was a suitably crazy website devoted to it.