Honestly though. For such a service. Id suggest mastidon sorta solves it. as anyone can already post from other servers.
So all you need is a parlimentary server. That alloows a second account for only MPs or those running for MP.
That limitation is hard to argue with. Dosent show any political bias. And only allows people like binface or any other nutty runner during an election period.
But they still have personal accounts they can link that allows them to comment without the parlimentary candidate Accolade during other times. Or with it if we some how end up with PM bin face.