I traveled for 5 continuous months straight this year overseas and used my personal California Amex hundreds (thousands?) of times including Apple Pay everywhere it worked and they didn't balk at all.

I didn't use any other card unless the merchant didn't accept Amex. 100% overseas charges for 5 months.

I'm pretty sure I could have kept going and they would have been more than happy as long as I continued to pay the statement every month!