Congratulations on being the first TamaTalk member to report getting their Tamagotchi ON!
Anyway, I don't have one, but I did import a Meets and didn't find it to be especially loud - it's quite soft in tone and volume, even when compared to, say, the 20th Anniversary Tamagotchi Mini, which you'd think wouldn't be as loud as it is. However, I don't have any other colour Tamagotchis to compare it to, so I don't know if the Meets/ON is quiet compared to them. I definitely wouldn't call it a loud device, though.
The screen thing is definitely normal, otherwise it'd chew through batteries like there's no tomorrow! (I wouldn't be too surprised if we someday see a rechargeable colour Tamagotchi in order to allow for more energy to be stored in that small space.)