Is iberia air a bad experience?

Context: honeymoon is less than a month away. We have one flight from nyc-mad which connects to mad-spu. Then flying home is american. We have premium economy and booked through an agent.

Recently i was just looking up travel experiences and reviews for iberia. And I am horrified. Not a single good review, everyone claims they mess up booking.

Getting nervous and I think it’s too late to change flight itinerary.

Thoughts on iberia if anyone had experience? For a regular trip I would probably be less worried but after wedding planning I really will just want to relax!

Thx in advance!