People who are looking to start a SE alternative but start with the idea of importing the original SE data dumps are already Doing It Wrong. Much of the issue that has led to the desire to fork SE comes due to the license of the posts and content, which lacks the NC (NonCommercial) component of Creative Commons. Without that component, any attempt to make a Fediverse alternative just ends up in Yet Another Endpoint that can be freely siphoned for data by corporations, for AIs, etc.