I mean like you could do 10x the damage by just redirecting an asteroid or even just gunning it with a fairly aerodynamic ship, its fantasy
But also the ideal elavator would have to be lightweight anyways so eith gravity it wouldnt work against itself, and therefore pretty easily able to burn up in the atmosphere (maximized surface area with the small size).
Also they wouldn’t have to be that long, a stable orbit isn’t super high up there - more like 100km or so.
And then again all this was about desolate planets in the first place