Since no one has answered you, JJV, I'll say hi and possibly help you. I'm new here, and I did exactly what you did about two years ago. I ran CAT 5e and went with a store bought Swann system with four 1080p cameras (2 Mp). It was prety intuitive but there were some bugs that I didn't like, so Ive always had my eye out for a better system.
Today, we have 3/4/6/8/12 Mp systems, but the problem with your and my set up and 8 Mp (4k) is that Cat 5e doesn't cut it. I've been looking at the Hikvision DS-2CD4A85F-IZH camera, but a professional installer told me that if I didn't use Cat 7a, it would look like VHS tape quality video. I don't know if I believe him, because Cat 5e can handle 200 Mbps and the camera's compression can compress 4k video to that limit. This is a guess, though, and before I install such a camera, I'm going to replace my cables with Cat 7a, per his advice.
I've heard that Hikvision and Dahua are comparable, but each one has a small set of outstanding cameras. On another forum, some people there tried desperately to vector me to 2 Mp cameras, in particular to what they or their buddies sell. The advice here is to be careful about what people will advise you to go with. If they're salespeople, they could be highly biased. Maybe by saying this, it will wake up the forum, and they'll come in with their six shooters blazing away. At least we'll get a response!