I don't think user-generated ads are a long-term sustainable business model but I DO think user-generated ads would produce a cambrian explosion of shitposts that would probably keep the lights on for like 2 or 3 months
number of guys who would spend $200 to e.g. send the entire website a link to the wikipedia article "List of Fictional Badgers" is not large but also not zero
In lieu of algorithmic boosting of posts, Cohost should adopt Tumblr's recent "innovation" that they call blazing, where any user can pay to boost any post on the entire platform to appear on more people's feeds.