For the sake of my own interest is THIS the fader you're talking about:
Because if it is then why not just lower the level, save as a Mixcraft template, and then tell Mixcraft to load that template when starting up every time???
Or you get real fancy and get this (but follow the same procedure as above):https://www.sonalksis.com/freeg.html
Of course and as has already been pointed out: the above workarounds will cause a problem when mixing down if you forget about it when mixing down.
On the other hand you could get real simple and just turn down the output level knob (monitor or phones) on your sound device???
Here's something you could try: right-click on the small volume icon in your Windows task bar and select Volume Mixer. Turn the volume down on Mixcraft.
Easier still (although in Windows 7 Pro you would turn down the playback volume of your sound device i.e. Mixcraft isn't presented as an option. Correction!!! See below!!!