I don't know.
If I look at college football, it's not always reasonable rankings. If I look at industrial companies, tech companies or banks it's not always reasonable.
I saw the highest paid coach in sports with a publicly available salary was a soccer coach in a team that has never won the Euro club championship and not even top 10 in finances. So it's obviously not always straight forward.
Other things to factor in, I would guess, are how large the whole salary bill is for the coaching staff. Like if you have expensive OC/DC. In this case though, Bears would fall short behind the Chiefs by a few million miles, question is does that affect how much they will pay the head coach or not. I don't know, just thinking out load.
But ofc, if I could take a guess based on nothing, I would assume that Reid makes more than Eberflus but I wouldn't bet on if he makes more than the Harbaugh brothers, Payton, Tomlin or even Shanahan etc. And there might be someone random cause the owner was rich and fukked with him on a personal level.