Try i3 as a Window manager. Put every app in a separate single window, and instead of alt-tab you use, e.g: alt+1 terminal, alt+2 browser, etc... You can have as much workspaces as you need and assign applications to specific workspace. This way I always know where every app or category of app exists. And this mostly works on default i3 config, no learning curve.

I started off using Alt F1-F12 (like the console), but I've found zero problems using bare F1-F12 with no modifier.

That sounds interesting, I'll try that, thanks!