The more readable wikipedia requires horizontal scrolling. (But also note YouTube includes too much whitespace, making the video small. This is a recent, annoying, change that I haven't created a tampermonkey rule for yet.)
Serif fonts work very nicely with sufficiently high DPI, or if they are designed to withstand low DPI like e.g. Georgia. Is there any way for a website to know if it's running on a high-DPI screen?