Wilo para heating circuit pump makes noise

We moved into our new building in December and are slowly running out of options. My wife cannot sleep because of the noises. The plumbing company has no clue and refuses to come. It all started after moving in; the heating circuit distributor was very noisy and could even be heard in the bedroom. We then called our plumbing company, which still hasn’t completed all the work, and informed them. After they finally came after a month, they just turned the Wilo pump down to level 1, speed 1, and the boss said it should be quiet now. It did improve somewhat from then on but was still audible. Then, about two weeks ago, it got louder again, even though nothing was changed. We even lowered the Bosch Compress 7000i AWMB at night to make it quieter. But from that point on, it didn’t help at all. Meanwhile, the Bosch customer service came as well but unfortunately couldn’t do anything either. He said we should get an expert because we have to live with the noise since the pipes are probably too narrow, or he suspects constrictions or bent hoses. When the valve on the HKV was closed, everything was quiet. On Saturday, another plumber came to help us. He said you only have problems when the flow rate is at 1 liter. We had a hydraulic balancing done for the KfW, but it has been adjusted 10 times by now. The plumbing company that installed everything also changed it again. The circuits were then between 0.8 and 1.5 liters depending on the length. Bosch customer service told us that this is also how it is supposed to be done. The other plumber who was here said he sets all the flow rates to 2 liters. The noise was now barely noticeable, but now the Wilo pump is whistling; it sounds like a tinnitus noise. It is terrible. We don’t know if it was already there before, and we just didn’t notice it so much because of the noise from the tiles. But now it is there, even at the lowest Wilo pump setting. (Para 25-130/8-75) What else can be done now, or what should I advise the plumber? He is clueless himself. Do I even have a chance against such noises with an expert?