While there aren't visibility-boosting features, don't downplay SEO on the app stores. That is, if your's is the kind of extension that people will be searching for when looking the solve their problem. The Chrome store also shows a bunch of 'related' extensions at the bottom of every listing. It can't hurt to show up there.
Also, since you don't mention it, list on the Edge Add-ons store. My user count over there is ~40% of the Chrome store number.
Great call on expanding to other add-ons stores. I'll need to look into compatibility and find a Windows machine to test...
The Edge store was stricter in some ways but I find I can submit pretty much the same bundle to both. Note also that Edge runs fine on MacOS.