Install on eaves from attic

Twenty-five feet isn't all that high, especially with a cherry picker. What you're trying to do with mounting a heavy PTZ from inside is like re-inventing the wheel as a square object. The next suggestion is to get a professional to install it for you, at least the mounting portion.

From the Amazon listing, this camera weighs 1lb but is a PTZ. Not really heavy. I've had professionals out to install the larger, heavier PTZ. That did not go very well.
 
If the camera is strictly an overview to observe what is going on, a 2nd story location is a great place and depending on the lay of your land, you can probably see more in the neighborhood that way. As long as someone realizes that they will not IDENTIFY at that location and have other cameras to do the IDENTIFY, it is a great vantage point.

A PTZ on the 2nd floor with its incredible zoom works well because it "flattens" the angle as you look further away, so someone 300 feet away will usually be a much better angle than the 1st floor that may have a bush or lamp post or car get in the way at the longer distances.

Now the downside is the closer they get to the PTZ, the more the top of the head you see, but if you have other cameras to capture them when they get that close, then a higher PTZ makes a lot of sense.
 
If the camera is strictly an overview to observe what is going on, a 2nd story location is a great place and depending on the lay of your land, you can probably see more in the neighborhood that way. As long as someone realizes that they will not IDENTIFY at that location and have other cameras to do the IDENTIFY, it is a great vantage point.

A PTZ on the 2nd floor with its incredible zoom works well because it "flattens" the angle as you look further away, so someone 300 feet away will usually be a much better angle than the 1st floor that may have a bush or lamp post or car get in the way at the longer distances.

Now the downside is the closer they get to the PTZ, the more the top of the head you see, but if you have other cameras to capture them when they get that close, then a higher PTZ makes a lot of sense.

Exactly. My home position for the front camera looks down my sidewalk to the driveway. The DeepStack integration lets me know when a person is walking up before my doorbell cameras notice due to the geometry of the house.

The 25x zoom really does gives me a good view of things happening down the road and one needs to be high up to look over the bushes, trees and other stuff.
 
I considered mounting a camera to the deck fencing, but I was worried about wind shaking the fence and vibrations from people walking. The FOV would be pretty limited, however, since we park a vehicle 15 away.
 
Not trying to persuade you to use a tall ladder or go beyond your comfort level, but I have found that if I take a little extra time to make the platform the ladder is sitting on LEVEL and STABLE (so that it doesn't slip or move from side to side) that going up those heights isn't as bad as it seems. But to each his own and good luck with your project!