I'm surprised no one has mentioned Arlo here.
https://www.arlo.com/en-us/
I just got a few, and while they aren't perfect, they're working quite well for me.
They're wireless (not sure if it's Wifi; you have to have a base station from them that plugs into your ethernet) and weatherproof. They're also battery operated. So installation is really extremely simple - no wires at all for power or network. You can basically put them just about anywhere, the caveat being that you don't want to put them anywhere someone could easily grab one, because the camera mounts to the base magnetically, so it can easily be removed.
The iOS app and web site are pretty good, if maybe a little slow to show live pics. You get, I think, a week of cloud storage for your videos for free. I have each set to capture 10 seconds whenever they sense motion. So far, they catch 90% of what's going on, maybe more.
Battery life could be an issue, but I've had mine up for weeks with the included batteries, and I'm still at full on all cameras. And since I've tried to put them in hard to reach spots, changing the batteries will take a bit of work when the time comes.
They run about $150 each on Amazon.