Key takeaways:

• if someone wants high-contrast on some websites, does it mean for every websites?
• go for the accessible version first: high-contrast except for @media (prefers-contrast: less)
• why not fixing color contrast by default?

Some browsers implements customization such as Arc https://resources.arc.net/hc/en-us/articles/19212718608151-Boosts-Customize-Any-Website