This is a partial list. Any specialist in any subfield of the discipline could list a large set of open problems. Nearly all have broader significance.
In my own specialty (industrial organization) unsolved problems which would be of interest to readers here include optimal regulation of platforms and two-sided markets. Theory and empirics are difficult, so regulators are to some extent fumbling in the dark a bit. It is not at all clear how to regulate (for example) Amazon’s offering its own versions of products sold on its marketplace OR what the right tariff Apple should charge for access to the App Store is.
Extremely confident claims that such behavior is permissible or should be forbidden are likely unsupported by any careful analysis one way or the other.