Ok I'm exaggerating. Or am I? I'm on Bunsenlabs Helium (Debian 9). I've installed monodevelop and monogame. I created a new monogame project and tried to build it. Successful build, but no executable. I've googled the issue and found a few solutions. Installing mono-devel, and mono-complete. No dice. I've tried "Clean all" before building, and nada. The only other solutions seem to involve creating other project types with specific settings which...doesn't really help me if I want to use monogame. Thought I'd ask here before trying my luck on stackoverflow or somethin. EDIT: Ok so the problem seems to have solved itself? I just opened the project from the file explorer rather than from inside monodevelop and it built...fine. Monodevelop is still trash though.
MonoDevelop on Linux has only started to degrade over the last few years. As you probably know, it originated on Linux. But in recent years, especially after Microsoft acquired Xamarin and re-branded the Mac build as Visual Studio for Mac, Linux support has taken backseat. If you compare MonoDevelop 5 years ago to MonoDevelop now, 5 years ago it looked and behaved like an GTK app everywhere, even on macOS. Now it looks like a Mac app even on Linux. Microsoft seems to be investing most of the development into the Mac port, where most of the users are, and only applicable items make it back to Linux. VS for Mac recently got a native editor which is based on the Windows one complete with multi-cursor editing and better intellisense, while MonoDevelop is still stuck with the same editor it's had for a long time. You might have a better experience with Visual Studio code. You can use it with MonoGame as long as it has the functionality you need. I haven't tried it for that, but a quick search brings up a few results with tutorials how to set it up.