I would definitely get several quotes. The differences were really significant for us. For visually similar doors from different manufacturers with almost the same equipment, there were differences of about €3,000. Even two quotes for front doors from the same manufacturer, same model, same equipment, differed by €1,000!
We are getting a front door without a side panel. Made of aluminum, with triple glazing (with laminated safety glass), 5-point automatic lock and fingerprint scan, anthracite structured outside, white inside, leaf-overlapping on both sides. We are paying €3,600 including installation, and I believe that is already very cheap (we kept wondering if the salesperson had made a mistake). The manufacturer is Inotherm. The other offers were on average €4,500 - €5,000 including installation. As I said, without side panel but with automatic lock, fingerprint scan, etc...
So your quoted price seems realistic to me. But it’s always a question of what kind of equipment the door has. For example: with double-sided overlay panel, 3-point locking without automatic and without fingerprint scan, with double glazing, etc., it would feel rather expensive for me. Not with "better" equipment. But maybe the region matters too. We live in a rural area. It is often cheaper here.