Thank you. I do see that "You can earn a referral bonus no matter which Card your friend is approved for.”, but am wondering whether, as the webpage also states, "They choose a Card from all available American Express Personal and Business Card offers."

https://www.americanexpress.com/en-us/referral

The following too seems to say that it’s not necessarily _any_ other card.

"How to Refer a Friend to an Amex Card You Don’t Have [Step by Step]

Here’s the cool thing about the American Express Refer a Friend program: you can earn a referral bonus for a credit card that you don’t have. This is a nice feature that’s different from the other major refer a friend program offered by Chase.”

Step 4 "They will then see all of the other cards they can apply for using your referral code. As long as your friend sees Referral Offer by the credit card details, you are eligible for a referral bonus.”

"When referring a friend to a credit card you don’t have, it still has to be in the same “family” of credit cards.”

https://upgradedpoints.com/amex-refer-a-friend-program/