I think you will find this conundrum on any software you switch to. FOSS is hard, and needs a big enough community of motivated people with the right skills to make a project successful. People are largely doing this work as hobbies; it's hard to fund such projects. Doable but hard.
The most obvious alternative to go for is the Reddit code base which was open source and has been forked as Saidit. This is the most likely place to find something mature enough and feature rich enough for what you may need but again whether things will progress is another conundrum as who else is maintaining or using that codebase?
Lemmy and any other project like Kbin will need people and work to get it where you want, not just suggestions and a list of requests. The problem is not a lack of interest in achieving what you want from Lemmy, it is realistically that it is a small project team with a big task on their hands and Beehaw are not it's only users.
Ultimately Lemmy may not be the software now to do what you want for your community. Federation may also not be the right thing for a community of your ethos. Maybe the simplest solution is complete defederation and build the community in an environment you can completely control, even with the limits Lemmy current provides with it's software. Come back to the fediverse when you feel the software matches the ambitions, but in the meantime build the community you want.