Great recap. Boosted posts would definitely help out on the revenue side.
Could act as defacto ad revenue and IMO would be better than direct brand advertising in the territories. Just brainstorming, but I could maybe target some sports newsletter writers who have substacks to come do a weekly boosted post on the sports sub and they use it as a way to promote their newsletter. Maybe I pay the boost on the first one.
This also has the added benefit of the fact they will likely promote these posts to their existing audience which could bring more people to SN.