The XPR only holds 1000 contacts, minus however many groups etc.
To get the most out of this limitation, I go to Brandmeister.network -> Data Visualization -> Contacts Export and grab the contacts from the talkgroups I use most. I sort that by number of transmissions (high to low) and import as many as will fit into the radio. This sounds tedious, but it takes 3 minutes to do, and can be updated any time.