The only thing a website can know, is, that "someone with a screen resolution of 1920x1080 pixels visited www.Photopea.com at 18:37". It can be useful to know the number of visitors, or the usual screen resolutions.
Which one of those do you need to know usual screen resolutions of users? Or maybe there are some other reasons those all get contacted?
(You also missed some "minor" details like IP addresses and fingerprinting profiles overall, and I'm honestly not sure if you are as ignorant as you act or just pretend to do so, and which one would be more offensive)
Like really, if you open a website for the first time in your life, what kind of secret information could it know about you?
That on its own should give you pause. But that data is then used by companies like Facebook or Google to allow the highest bidder to alter that users behaviour - by getting them to believe some propaganda, to vote for a political party, or to spend money on something they don’t need.
That’s the business model. That is how you make money on your site.
There are other ways of making money – I’m sure that had ad revenue not been available you would have found a different way.
