The airline was deliberately established to undercut and put Norwegian Airlines, and any other pretenders to low-cost transatlantic flights, out of business.
They must have had one heckuva good time machine to pull that off.
Norwegian Air Shuttle (the low-cost carrier, now out of business) started operations in 1993.
Iberia, which is still a huge airline that currently flies all over the world, was founded in 1927.
Level (aka "Fly Level") has been around in one form or another since 2017. It's owned by IAG, too, and is an LCC ("low cost carrier"). Level flies short-haul to a handful of western European cities, and long-haul to a handful of American cities plus Chile and Argentina.
Iberia is fine, it's like any other airline. Some people have good experiences, others don't. They often sell cheap tickets, which is what everyone demands (though some complain about the very things that make those tickets so cheap). Like any other airline, they may or may not live up to your expectations. Most people seem to be OK with them. I've flown them a couple times, it was no big deal. YMMV.