I bumped up the default zoom setting in Vivaldi to 200%. My eyes are thanking me.
Vivaldi also lets you zoom the user interface scaling. Why is this not a standard feature everywhere? Not just in apps, but across the operating system. I remember this used to be a thing on Windows, and I've seen it as an option on the Linux distros I've tried recently, but macOS only gives you the option of scaling down the screen resolution, which I have a hard time wrapping my head around — are they that precious about their UI? (Evidence from Big Sur suggests not.)