It’s a well known fact that some types of astigmatism (the kind I have too) causes light text on dark bg to look blurry i.e. the text to be somewhat doubled.

I got a pair of glasses made that only fix my astigmatism to use with computers.

Same. My myopia is minimal but the astigmatism bad enough that I have to squint super hard to read non-giant text without glasses and even then it’s 30% guesswork. So the computer glasses correct only for astigmatism. But it’s almost equally bad in light mode and dark mode.

I have separate distance glasses (also with astigmatism correction) for driving and such, but they give me headaches if worn indoors.