(solved) low res window size that fits fullscreen 16:9

Hello, I am trying to find a low res resolution that will fill the screen at 1080p and 720p in NW.JS

I had my low resolution pixel art game running at a window size of 480x270 which looks fine and fills the screen at 1920x1080, with scaling set to letterboxed integer, but in 1280x720 it is surrounded by large black borders, which is confusing me as it is also 16:9. any other fullscreen scaling options either do nothing or make the pixels uneven.

Are there any resolutions I can use, similar to the window size I am using where I can have full screen (or as close to), square, clean pixels at both 720p and 1080p?

Here's a list of True 16:9 Resolutions https://pacoup.com/2011/06/12/list-of-true-169-resolutions/

They've highlighted one's divisible by 8 in green, your pixels will scale fine if you stick to one of those

1920x1080 and 1280x720 are both multiples of 640x360, or even 320x180 if you're willing to go that low.

The reason why you can't have perfect letterboxed fullscreen with 1280x720 is because it's not a multiple of 480x270, so it goes to 960x540 and add black borders around your game window.

Thankyou for your kind assistance!