We do not have an ERV/HRV. Half of the house is pretty old and drafty, so it probably wouldn’t be critical immediately. But probably worth looking into.

Here is a photo of one of the knee well attic spaces with a vent at the top: https://imgur.com/a/U5GcyLP

No insulation in the attic floor, except for a couple inches of 80yr old insulation where they added a second floor on top of the first floor and didn't put in the effort to remove it. Newer parts of the house you'll just see the ceiling drywall from the room below.

There is roughly 2-3" of spray foam under the roof decking/between the joists. Colorado front range for climate reference.

Even with spray foam insulation under the roof deck? From everything google seems to say, you usually don't want ventilation:

https://www.google.com/search?q=spray+foam+insulation+attic+ventilation

However, I'm not the one who did the insulation or the venting, so I'm trying to find out if they broke the "rules" for a reason I can't think of.