Have you chosen the correct colour space in Affinity Photo. sRGB is different form RGBf, or Adobe RGB (1998). Apple RGB, your own Monitor RGB (etc.) colour space? RGB looks by far more bright and crispy than a printer usually can print out. This is why you can adjust your monitor to the colour space of your printer and as well your photo/image/grapphic design software to the target colour space (could be printer for print out, or web, or just to be viewed on your monitor). You have to use a colour space in your software according to the final taget you create or edit your picture for.