There’s no need to use Caps Lock when rendering. You just minimize AE.
Caps Lock is to prevent screen redraw while working in AE. Sometimes you need to work in the timeline copying keyframes or whatever, you don’t need to see the comp window redraw itself, and the redraw would slow down your work. That’s what Caps Lock is for. So if you’re rendering and want to avoid Comp window redraw, just minimize AE and switch off Caps Lock.