You could carefully collect evidence, investigate clues, and build your case against key suspects, or you can do what the Blame Game Commander Deck does and accuse everyone at once
Put X +1/+1 counters on Krav
You cant use counterspells against schemes
Despite having a low budget, Siona is one of my most powerful paper decks: not only is the deck an Aura Enchantress deck, which has an incredibly deep pool of strong cards to work with on a low budget, but it's also able to quickly and consistently combo off thanks to the interaction between Siona, Captain of the Pyleas + Shielded by Faith to generate infinite Soldier tokens and the backup combo of Siona + Reins of the Vinesteed + a sac outlet like Blasting Station which similarly generates infinite tokens to sacrifice and win with
This is, in part, because Maze's End is a solid (and extremely budget friendly) Pioneer deck and in part because among a huge number of Commander Legends : Battle for Baldur's Gate leaks, there have been some cards (including new legends) which care about the Gate land type