I found Firefish which is a better alternative to the standard Mastodon application. It’s compatible with Mastodon and has better features. It allows users to create web pages and the character limit is 3,000 instead of the 500 on Mastodon. It feels like a good limit for the type of site that it is. Plus this means that it can handle long posts from users on customized Mastodon instances.
The userbase is not that important with activity pub. If the features are good they can grow slowly and still enjoy the whole fediverse. Of course it is important to have users at all. Otherwise it doesn’t make sense to put work on the software.