What does Prossh need to be cEDH?

I've been playing cEDH since 2014 and have been piloting Prossh for the entirety of this time, but as of the last few years I've started to notice that I can't even seem to compete when sitting down for a tournament let alone practice games. Is it even possible for Prossh to be a contender in the current metagame, and if so what is needed for it to be possible?