Reversing default window size and letterboxing behavior

Is there a way I can reverse the default size of the Tor Browser window? I like to split the window to use only half of the screen, and that used to work fine in the past but with the new change I get huge bars on both sides.

For example, if I were to open a Tor Browser window and a file manager it will now give me two fat bars on each side, when in the past it would fill out the entire browser window with the website content.

The letterboxing is not the only problem, I also think that the new size is too large, so I simply want to reverse it.

I found privacy.window.maxInnerWidth and put it to 1000, this reverses the default size but not the letterboxing behavior.

letterboxing is controlled by privacy.resistFingerprinting.letterboxing