Thoughts
If I were running Cohost, (aside from moving infra to Cloudflare) I'd require you to pay to make more than 10 posts per month.
So there would be a free tier, but hopefully 70-80% of MAU would be paying. The consequences to that seem pretty obvious to me. The site would be small and would stay small. So your costs would go down. You could afford to pay a couple of devs. You could look at decreasing the cost or increasing the number of free posts according to your actual costs. You could implement gifting subscriptions either to an individual or to the community like Twitch, or some other sort of "gleaning". Anyone can sign up, anyone can still read posts. This would put you in the "small amount of money from a large amount of people" area.
And this has been proven to work because Are.na has been doing it for years (200 free posts, $7/month for unlimited posts, 4 full time employees, 15,000 paying users). (Cohost for contrast is seeing 30,000 monthly active users, <3,000 paying, and they're trying to support 4 full time employees.)
The reason I don't foresee Cohost's current plans working out is this line: "the best way for us to make up for our deficit is to have more active users. the best way to have more active users is to make cohost better." I don't even know where to start with this because it's just wrong. 1. more active users will increase costs (on paper this isn't true, but in practice it is). 2. users don't move to a platform because it's better / users will use even a bad platform if there's a reason to. 3. Cohost's primary audience is gay Luddite furries, which is a limited number of potential users. 5. Cohost's UX is already better than every other social media site 6. Cohost's interface is a Tumblr clone which is extremely confusing if you've never used Tumblr before.