You are too soft! I do recognize myself quite well. Too thoughtful... Put some real pressure on those to whom you paid a lot of money for a job. There are no cosmetic defects. A defect is a defect and it must be fixed.
Here I would like to disagree at several points. First of all, it’s not about "pressure" at all. It’s better not to puff yourself up and try to increase pressure by "not being soft." Rather, it’s important to write down the identified defects, discuss them with the contractor, and work out a solution. The defects and the agreement on their removal/solution must be recorded in an acceptance protocol and signed by both parties.
The problem is the lack of expertise. Without the presence of an expert, you will be given a whole range of plausible explanations, and—often under the pressure of handing over the keys—you will be satisfied with these and sign the acceptance protocol, but then without the defects being recorded. The problem: you have then accepted the work—with this defect—and no longer have any warranty for this defect. A very unpleasant situation.
Another problem is that you can only recognize smaller—visible—defects. The expert will be able to identify a number of—truly expensive—defects, if they exist. Well-invested money, also for peace of mind.