Dell Precision 7550 fan whistle

I received my Precision 7550 this week (Xeon 5.3Ghz, RTX 4000, 4K screen, 32GB ECC, 1TB SSD).

Happy so far except one thing.

Apart from the normal white noise which all fans make, there is an additional whistling noise. Mostly from the right fan. If I remove the bottom cover there is much less of it or almost none.
I suspect the whistling comes from the sharp metal edges on the fan casing around the impeller and when the lid is present there is some air flow restriction and the air has to travel even more around those edges, which creates the whistling noise.
I varies with the rpm.

Will probably try to put some kind of circular edge around the fan opening. Maybe it helps. Another solution may be to cut open the lid below the fans, but I won't do that in this expensive new laptop.

Anyone has similar problem? I think this is a flaw in the design. Haven't spoke to Dell yet.