I need a vacuum cleaner to pick up kitty litter that my cats paw out onto
a
hard surfaced floor that has to be vacuumed at least twice a day.

Get one of those litter box mats. I stuck them in front of our boxes and
it's really cut down on the amount of stray litter. And if you're not
already doing so, consider a covered litter box. That and the smaller
clumping style litter as it's much easier to keep clean.

Something lightweight and easy for an old lady to use. I now use a
Bissell 3-Way
Bagless that doesn't do much other than scatter the litter.

I use the hose attachment on our Sebo vacuum. Most all rotating beater
heads will scatter the litter. Also consider using those wet-wipe swiffer
mops. Those work great for picking up stray bits of litter.