Trouble finding a motivated co-founder

Be successful first, then go looking for a partner. That will be a lot easier.

You are in the 'chicken-and-the-egg' phase, you need to get past that. One option would be to simply pay someone for this role for a while to make it easier to achieve the success required to get someone on board who will do it for an equity stake.

seems about right. you're doing fine. cofounders require crystal clear skills and/or high trust. otherwise they become a negative. ugc can be many things. i am curious what type of content.