The best dark theme for instagram in my opinion because it even has a black font when you reload the page. The background could be a little "grayer" in my opinion so that there is a better distinction between the background and the photo frames.

When clicking on an image in instagram, the image's sub-window always appears at the top of the page, effectively breaking instagram as you can't scroll when an image's sub-window is open

same parts are not invisible to see like some text, lines Logo, etc.

dark mode ok but photos go higher and are invisible because of that

This makes Instagram so easy on the eyes. The only change I would make is an option to make the text white or choice of color because the text default for Instagram is black so you kinda have to mouse around to find the likes button and other stuff. The post text is white but all the other site stuff can't be found.