Found a fix on Reddit

[AirHeadsbuirse]

// Find all the "Add to Card" buttons on the page
var offerButtons = Array.from(document.getElementsByClassName("offer-cta axp-offers__global__fluid___15Bk5 css-1duq00z")).filter(btn => btn.title == "Add to Card");
var index;
for (index = 0; index < offerButtons.length; ++index) {
console.log("Clicking offer button");
offerButtons[index].click();
// Wait 2seconds to be nice to AMEX servers :)
await new Promise(r => setTimeout(r, 2000));
}

https://www.reddit.com/r/amex/comments/nrlmbs/mostly_automated_way_to_add_all_offers/

[cjangrist]

var offerButtons = Array.from(document.getElementsByClassName("offer-cta")).filter(btn => btn.title == "Add to Card");
var index;
for (index = 0; index < offerButtons.length; ++index) {
    console.log("Clicking offer button");
    offerButtons[index].click();
    await new Promise(r => setTimeout(r, 1000));
}

worked for me