Linux

You essentially have 3 options with open source audio apps (there are some good closed source options too, like the great Reaper, Tracktion Waveform, and BitWig Studio, but I will focus on foss solutions here):

• Ardour. This is the premier foss app. In fact, a fork of it is closed source used by a big audio manufacturer. So it's the best tested foss audio software out there. It can do both midi and recording sessions, but it's best for recording stuff. However, the new version, expected by end of this year, will have major midi updates that probably will put it on top of the king of midi in foss:

• LMMS. Best for Midi. If you're doing electronic music through and through, this works great. The only downside it has it does not support vst3 plugins (soon enough, this can become an issue, even if you say that you don't care about plugins). You can still get vst3 support by loading them via the Clara plugin (basically, it acts as a plugin for other plugins), but that can be unstable.

• QTractor. This one is an odd one out. It's a bit hard to get it going (it requires external synths and some patchwork to connect audio devices), but it is very powerful and I'd say, a more sane UI when editing. It comes with no plugins at all, but it supports all plugin standards for linux. Basically, this one requires more setup, but once you set it up, it gets going easier.

Alternatively, if you're actually interested only in rec. audio editing (basically cutting, pasting etc), simple stuff, there's Audacity.

If you're using Ubuntu or Linux Mint, Zorin, PopOS, install the ubuntustudio package for pipewire (can't remember how it's called you need to search for it). It sets up pipewire audio correctly, so more plugins/apps work out of the box (without it, for example, Bitwig studio doesn't even make a peep...).