Amex might not have given you a high limit since you don’t have a history of high limit cards and wanted to see your payment history first.
My best guess at Prybar is that they don’t want to be the first lender to take a crack at you with a high limit and since Amex does 3X CLI at 61 days and then 181 days. You can have the limit up to 9K.
I agree it’s a low limit. I got 2K with them with scores of 610 EX at app and collections. I was also a AU on another Amex card for 2 months before app’ing and made all the payments through my own login.
Not sure how credit card companies factor in new mortgages but that could have played a role in the low limit as well.