Pages keep quitting at the programs startup screen.

I'm guessing (because you didn't include the informationin your post) that you haven't yet updated your operating system to the current version—maxOS Big Sur 11.4.

Doing so should eliminate the problem with Pages (and with umbers and Keynote.

Regards,

Barry

Make sure you are running the latest version of macOS (currently 11.4) and Pages (currently 11.1).

Update macOS at System Preferences > Software Update.

Update Pages via the Mac App Store.

SG