I read your post. You're not showing me anything I don't understand my friend. Here's the thing, you can have something in common with a coach and still be radically different.
What you're missing is that you can be 100% factual in your words--you are--and still have a comparison that doesn't find many things in common. You're using the 'comparison' to find things in common. There's barely any once you get to the specifics. Because you're using comparison to essentially say "look what they have in common," and there's little, then it's a bad comparison. I might use the comparison to show how there's little in common. That would be a good comparison.
There is a world of difference between their success. Reid was arguably a HoF coach when he left Philly. Quinn isn't that. They don't have similar winning percentages, deep playoff runs, they coach opposite sides of the ball, one is a true blue player's coach and the other more is more laced up. That comparison shows massive differences.
They both lost a SB. Yes, they did. How indicative is that of their similarities? Well,
https://www.profootballhof.com/news/super-bowl-coaches/ lists all the losing HC's. How much in common does that SB loss show commonality between Quinn and Bud Grant, or Gregg, or Carrol, or Martz, etc.? It is more specific than 'well they're both head coaches' but it doesn't speak to commonality.
Your comparison, to show commonality between AR and DQ is akin to apples and oranges.