You can always switch off the camera's built-in IR Illuminator and install a separate illuminator positioned to not light up the wall in question.
With a separate light source, you can get the position and aim of the light right, and even baffle the light to keep it from lighting up anything that would throw off the camera's exposure, all without sacrificing the ideal aim of the camera itself.
And that illuminator doesn't need to be an IR illuminator. You can also just install a white light with an "on at dusk, off at dawn" sensor to light the area in question. And that can let you keep the camera in color mode all night, which can be a good thing.
Also. providing more than one light source is good. You can eliminate shadows and reduce the contrast (get more even lighting) by using more than one light.
So you have some options with the lightning, too.
While I appreciate the inclusion of IR illuminators in cameras, they're like the built-in flashes on most cameras. They're so close to the lens that you're asking for problems. This is why photographers often use off-camera flash units, umbrella reflectors, multiple light sources, all manner of flash modifiers, etc., to get the best images.
We often do well to employ the same lighting methods used by any other photographer.
There are a lot of good tutorials on line for photographic lighting. Some of the techniques may not apply, but understanding the concepts is a very good thing for security camera use.
Here's a page with a number of good tutorials.
10 Photography Lighting Tutorials From Beginners to Pros
Check out the "Three rules..." video. Basic stuff, but often completely unknown to security camera users.
People should really understand photographic lighting and give that as much emphasis when designing their camera system as they do the other aspects. Security camera use IS photography, after all. And nothing is as important in photography as light.
