Amex does have excellent customer service.
As for getting an airline miles card or a travel rewards card, you need to know yourself. It sounds like you wouldn’t let yourself be in debt. If you pay off your balance and track your spending then an excellent travel rewards or airline miles card can help you get more out of your purchases. BUT, you have to make sure you aren’t spending more than you have and that you pay off your card every month.
We pay our card off so a credit card becomes a convenient tool for purchases that offers us other perks as well.