Not sure what you mean. Most teams don't draft QBs to be backups, at least in the early rounds. We are in a perilous situation where we have a starting QB who has now gone out in what might as well be back to back years at pivotal points. A backup with starting potential is a 100000% percent need with a vulnerable starter, which we have.
I would also counter that our entire defense does not need an overhaul. There are peices, sure, priority being the line, but entirely? No. I'll give you RB and we are just injured this year on OL, it is manageable, just need to use later picks for second and third strings.