HEllo , does anyone knows how could I do to make a large map projection? my map is 21kx10k and is the classic equirectangular, but the program I used to use for make the projection only accepts smaller sizes like 4k at max , so how can I do to project big maps?

Also eventually where can I upload a map that exceeds 80 mb and of the size above? I tried deviant art but doesn't work.