E only coach,whicj is not the same thing iherwise your comments illustrate an extreme lack of understanding of how coaching staffs work.
The ibtercommunicstion within a staff and strengths of individual staff memebers come to the forefront of successful staffs regardless or "title" or "stated organizational responsibility".
More examlles..
Kaufusi was the ine who got ZIGGY to play DE.

NOT the DC who was also the HC. Bronco had Ziggy at olb and wanted him to stay there.

Conversely there are plenty of staffs where a coach wasnt allowed to do what he wanted and the hc overuled him.
My nephews AAU B Ball team 3 years ago the defensve coach wanted to run man to man and a diamond and 1,but th3 hc kept putting the team into a 2-3 zone.

The vwdy firsr team i coaches the team had won 3 games the year before and 3 the year before that. The HV aaked me my nrother and two other friends to stop coaching from the fence during a prwctice and to actually coach for gim.
That team went undefeared...went to a bowl game.
We moved players completely around from what this 11 year vet hc had had.
We ran comletelt different iffense and defense suited to the talent on the team.
We onky allw3d 1 team to cross midfield the whole season, beating the repeat league champs soundly twice.
Then we got to the bowl game and the HC did something he hadnt done all year. He medsled. He moved olayers around,he called plays on his own without ketting his oc do it.. We were down 28-0 at halftime. At halftime he asked is what we should do and we made changes.
We still lost,but we lost 28-26.

So just because a person is called the defensive coach, does not mean That coach does not impact a team in any and all other aspects of the team.

Thus your point is moot.