I think its fine to target compatability with 99.9% on people with updated devices and not some random old 2020 safafi build

To be fair on this particular point, talking about iOS Safari before version 14 isn't "some random old build". It depends on your own users, but I saw plenty of 6-year-old iPhone user agents in the web logs when dealing with a doctor's surgeries app.

Even though I provided a direct link to wcag principles and guidelines, you still are too lazy to read.