I find that I’m limited to 2048 when using texture paint. I don’t know if this is a problem with texture paint, but with only one layer I’m guessing it’s a limit with the viewport. I can’t get anything bigger than 4k to display in viewport.
It’d be a huge help if I could get the viewport up to even 4096k. That last little bit makes a huge difference, since texture paint has to use power of 2 textures. 4k is so close, and yet so far . . .
think about what you are asking. Unless you are going to print a poster that covers a building, compute the resolution of your screen, the relateve size of the object, and how many actual pixels will be displayed. 2k to 4k is not close, it is 4 times as much, 64MB of texture (graphics ram), just for that one image. You video card may not handle it.