I would suggest starting the invite process with the people who were in the community before it went awry. You can also make a post about how you're starting a new community in the old community and explain what will be different in the new community. I belive this happened recently with the "196" community becoming the "oneninetysix" community when the mods made decisions the users didn’t like.
Being mod of the new community would allow for removal of unwanted users. Additionally, if you were admin of the instance, you could block other instances that had users that tended to not match your stance on issues.
Hopefully, that helps.
Paywalled.
Can someone provide an archived version?