Chromium-based browsers, including Chromium, Google Chrome, Brave, and others have a native dark mode stylesheet that can be enabled in chrome://flags/#enable-force-dark
It works to varying degrees of success depending on the site. Some sites become unreadable with it.
What I personally do is I have this flag enabled in my primary browser on my main computer, Brave on a MacBook Pro. And for any site that is severely broken I either skip that site, or if the site is important then I open the page in question in my secondary browser, Safari, and read it with its normal default style.
It works to varying degrees of success depending on the site. Some sites become unreadable with it.
What I personally do is I have this flag enabled in my primary browser on my main computer, Brave on a MacBook Pro. And for any site that is severely broken I either skip that site, or if the site is important then I open the page in question in my secondary browser, Safari, and read it with its normal default style.