Have a look at the section about automation.
Enable automation writing, either on a track by track basis or globally across the mixer. You can then compile your mix by fader (and spins to sends, eq sweeps, etc) automation which can be saved and tweeked. You can do this in one pass or many.
Having some sort of fader equipped control surface can help a lot with the process of compiling the mix automation.
When you have the mix with it’s fader rides etc to your satisfaction, then do the “Audio Mixdown” which is as you and others have said is basically a file render operation.