prores has many versions. PNG sequences are usually 8/16 bit 4:4:4, so any encoding would have to match that. If you need the exact same file size, prores is visually lossless but not mathamatically lossless, including its 444 XQ which is confusingly called 444 but only the alpha channel is preserved! the RGB values are log encoded compressed so there’s data loss.
Quicktime’s PNG video is a very small size, even smaller than quicktime animation, but again, its 8 bit, but at least its RGB is true 444. If you want no generation loss, you’ll need 10bit HD or 12bit (dolby vision) 444 encoding.
OpenEXR is pretty good but mostly overkill for file size, but has a small math difference error. The same with PNG seq.
Tiff and PSD sequences can handle 16bit with 0.00% loss if LZW compression is turned off.
FFV1 is a free 10bit 444 video codec but not standard.