I'm not sure it can be done that simply.
The "quality" of a site might be very high, but it gets little traffic.
A site might get lost of traffic, but very few clicks.
For someone looking at a site, it has to match their needs, too.
Example: One client might not want clicks, they want it for branding, and everywhere.

The less ads per page, the better (the best would be one ad on a page).

The number of ad units on my various pages range from 0 to 3; factor in my ad balancer setting too and my average page impression / ad impression ratio is about 1 : 1

I don't use Ezoic but if you read their blogs you get to understand how their system works. Ezoic's metric for determining ad unit optimization 'success' is EPMV (earnings per thousand visitors), not CPM or RPM.

The equivalent Adsense metric for EPMV is 'Ad session RPM'.

"Say you were a big advertiser who had to pick just one Adsense account to display ads with. What would you look for?"

Cost per conversion. This is literally how big buyers choose where to direct their highest priced campaigns. They'll usually "shotgun" some initial spend based on audience & view-ability then optimise the campaign by cost per conversion. This can be hard to optimise for from a publisher perspective. Once you have ensured that you are not "bad" (limit ads per page, no bots, no accidental clicks, good view-ability etc) moving from "ok" to "great" can be less clear a journey. Optimising for things like audience intent works (for instance, building content closer to the point of purchase), but can be hard to demonstrate.

For example: If you had a gadget site you might find that buyers guides ("The 10 best widgets to buy today") converted better for advertisers than less immediate content ("What top widgets we expect to see next year").

It's not a dashboard metric though... well, not in the AdSense dashboard anyway.