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.
I'd love to know where that setting is. As far as I've been able to see, I'd have to rebuild mastodon myself to be able to do that, and that's just less convenient for me than pulling the default docker images
I might be thinking about glitch-soc, which is a fork of Mastodon with extra features, some people have been asking for.