Prefer type of coach? An offensive, A defensive, or a middle guy?

There's not many examples, but they have already been pointed out to you. These former DCs and former OCs keep getting fired left and right while one of the last ST guys to get a shot has stuck for nearly 2 decades. You don't like Rizzi for some unknown reason or don't think he should get the job even though he's earning it, check.
No there are not many examples there are NO EXAMPLES
Every name that has been given as an example I have shown that they have more experience than Rizzi.
There has NEVER been a successful HC in the NFL that was not a OC, DC or a position coach in the NFL or a major college
Rizzi has only been a ST coach in the NFL. He has only been a HC at New Haven and Rhode Island
While I do like Rizzi and he may be a very good motivator he does not have an X's and O's background on the offensive or defensive side of the ball.
At least Campbell was a TEs coach and he even called offensive plays for 8 games, not very well but at least he's done it

HCs get fired left and right not because they were OCs or DCs. And most successful HC WERE OCs and DCs prior to becoming HCs