I've done this - At my first home the main runs of wire between house and garage were indoor-rated cable, but I used many zip ties and strapped the cables to the underside of a fence rail that provided sun protection.
There were two points where the fence didn't go far enough. So my solution was to slip some flexible plastic conduit over a ~4 metre length, and then ran that down, across a narrow access and slightly buried it, then up into an elbow that pointed down.
You can fit 3~4 cat5 cables in a couple of metres of 18mm conduit.
At my next home I used 13mm irrigation hose (the stuff used for home garden sprinkler systems) because its cheap. You can start three separate pieces of cat6 in there, but they don't go far. I barely got 2 pieces through a 10 metre run of this hose because friction increases with distance.
I run a Pi4 and a hard drive on one POE line, and a network camera on the other. This hose was buried under a paving slab pathway for protection, and has survived for almost 6 years without issue.
My oldest effort was the least successful. We had a need to run data cables between two adjacent prefab classrooms for a while, and due to people moving between could not run on or under the ground. So an aerial cable worked for a while. If you go this route, run a catenary of fencing wire and tie it off to eyebolts at each end. Then loosely tie your catX cable to that so the catenary is holding the weight not the cable.
At the eve of each building, put a loop in your cable so that any water will drop off, and not run along the cable and into your building.
Expect this to last no-longer than a year, probably less. White or beige or light colours will be better than dark colours because sunlight.
My cameras are all under eves/soffits and I've had great success even using indoor rated cameras outside, as long as they are physically incapable of getting rained on or sunlight on them. I also only use cheap $~40 aliexpress POE network cameras, which are no-great loss to replace if one does fail.