I just noticed there is no ad blocker on chrome, so that's hardly ideal when I run on a metered connection. So I guess maybe Opera and its data-saving mode will be useful there too.
Opera browser is a closed source and it comes with a bunch of bloatware installed.
Brave browser is a bit better and it is coming with ad-blocker but you need to manually disable some extra stuff.
Few other options you have are DuckDuckGo browser or Firefox.
It worked for me. But the images and the signature look weird in this mode. But it looks much better when I am reading or writing. I assume if I want to disable it, I can just follow the same instructions and disable it. Right?
Yes you can disable it anytime.
Just bookmark the link I posted and change to default Disabled settings.
You can also play with different inversion settings and see what works best for you.