I fear I may have lost family after correcting angle distortion the other day. No angle distortion here. Secret: get the camera down at the level of your (cat) subject. Hence, use the angled screen to take the picture at the subject’s eye level. Pretty easy. Most people don’t do it.
Flash has never been my forte. I use it very sparingly. The more recent cameras I use have better exposure than ever before. Flash will certainly help to brighten hooded eyes. Portraits? It is the eyes. Focus on the eyes. And, to be more effective, I think the subject should be looking right at you. … my opinion. After that, breaking the rules is what gives you something different. Better, worse, “keepers” are pretty easy to spot. There are so many bad shots….