Twitter labels all tweets as state sponsored already but they should do more. Not giving them a platform in the first place would be a good idea. Requiring the viewing of each and every tweet of these outfits by having to consent would be another hurdle. Make it so hard to engage that users simply won't be bothered to interact or share.
I don't have answers other than immediately shutting down these companies posing as journalistic outfits because they aren't journalists when they blatantly do Putin's bidding.