Yes, i am having this same issue going back to September/October 2019.  I have three different Amex Accounts  (Platinum, Gold, and Cash Back), with one employee under each card (So 6 cards total, three in my name and three in my employees names).  For each of the accounts, only my charges are importing into QB, not the employee charges.  It's incredibly frustrating.  I have found that if you login to Amex, and download the transactions into a QBX file, and then upload them into QB, both my card and employees cards transaction data will work its way into QB, but it's a painful process and Amex says they will "discontinue" the ability to download after May 1, 2020....I hope the get this figured out because I agree this is awful.

It seems that QB has now captured enough market share where they don't actually care about proper functionality.  QB online continues to lag behind QB desktop, and yet the price seems to increase about 10-15% every six months...i guess that's how they (Intuit) pay for those super bowl turbo tax ads hah.