DaVinci Resolve: Track with points outside of a window
The tracker is designed to track whatever you put inside the tracker's window.  It doesn't matter whether you want to track something in the middle of your frame or on the edge.  All that matters to the tracker is that it can "see" enough detail of whatever it's being told to track that it can lock on it in the various dimensions it can track: pan, tilt, rotate, zoom, and 3d perspective.

Your background looks really tricky to track because it's very low contrast (relatively speaking).  You could dramatically boost the contrast of your background, for the purpose of building a good track, then use that tracker data on the non-contrast-enhanced image.  Just use a square or a circle over a small but distinct area you want to track and it should be good.

BTW, now you know why people who need to do VFX use Tracking Markers