The speed may varies on the modem frequency too. In general laptop or pc's wifi runs at full potential of their power but in smart phone there is some excuses happens and also capacity of fetching signal is lesser than laptops

Looks fine if you are facing a problem like blurry images then please try to click photos where you have sufficient amount of light.

Your charging socket is damaged so please replace it.

I'm using note 10 plus from so long time and I'm not facing that kind of any issues with any lens (wide,main or portrait)

No it's not software issueIt's sign of water damage or dust placed inside the camera sensor. If I'm not wrong