I don't really care about that stuff tbh but I guess it is a good boost for social presence as it makes you stand out from the rest.

I am ~ 25 😉

I used postloop but once they sold and changed owners the whole site just went downhill, I don't even think the site is still up.

+1 for this, 2.0 backlinks are more powerful

I use MyBB for all my projects, been using them since 2011! I haven't created a custom theme but I have bought around 3 so far.

Many people will sign up and not post, maybe they don't like the content on your site hence why they dont engage?

I Used to run a offshore hosting company around 3 years ago, had around ~150 clients but ended up selling to not having enough time to run it.