New P6 questions problems

I've had my regular Pixel 6 for two days. I bought it from a third party importer in a country that doesn't officially sell Google products.

I'm replacing a 3+yo Huawei p20 Pro with a cracked screen and degrading battery.

I cannot replace the Pixel phone but I have a 12day return and refund window left, and I'm wondering if I'm better off getting a Samsung s21 in the same price range. Pixel 6 is 800+€ here.

Photo quality is important to me, and Pixel supposedly takes better photos, which is why I ended up with it.

I like the screen size, I like how snappy and resposive it is. I think still photos is good light and night mode are better than my Huawei.

Issues? I have a pink to green gradient that's really annoying me on white screens (Reddit is Fun, Discord, Facebook are the worst offenders). It's like a shifting green-pink gradient that moves around as I tilt my screen, but some part of the screen is always green no matter what angle I look at. My Huawei is completely uniformly white next to it. I did a side by side.

Is this normal for Pixel 6? I did Google green tint, and I don't seem to have the issue with dark grey and low light. Tried it out at 10% brightness and dark mode and no tint. Unfortunately dark mode gives me a headache so just switching so dark mode permanently isn't an option.

If this is normal for this screen though, I obviously don't have an excuse for a return&refund.

Secondly. Still photos with the main camera are really nice. But trying to take photos of moving pets/kids is a blurry mess. Is there a setting/mode I'm missing? It's ridiculously bad.

Thirdly. I can't get the front camera to focus properly. They're not bad. My pores are in focus, but despite tapping the focus on the screen I can't shift it to my eyes for example.

Out of all of these, the green shifting gradient on white bg apps is the most annoying to me atm.