I have returned my Samsung galaxy s20 ultra today as I found a spec of dust under the screen. It's an absolute JOKE! It's very annoying to pay so much for a premium product and then find it to have a defect like this. I'm hoping they can either exchange a new device or refund me, although I've been told it could be 14 days now due to Coronavirus and closed offices.
Weirdly enough, I do have a simular problem. My phone has got dust on the lens of the main 108mp camera! It's very strange, since it is a certified waterproof phone!
I have this issue too. Tons of specks beneath the protective film. Never had it happen with S10, S8, S7 etc. What the heck? Do I get it peeled off?
I've the same issue as you, super pissed. Now I've to send it to the service centre, which I hope they will just give me exchange my current phone for a new one.