Mono-Green Landfall floods the board with cheap green creatures and grinds via landfall triggers, so Flashfreeze is excellent against their entire creature-based gameplan. Rest in Peace shuts down Icetill Explorer's graveyard-land recursion and Escape Tunnel/Fabled Passage fetch value while also hosing their Heritage Reclamation sideboard plan. Exorcise picks off Mightform Harmonizer, Bristly Bill, or Mole Man cleanly at instant-speed sorcery timing. Settle the Wreckage is weak here since they rarely overcommit into a single alpha strike, and Spell Snare has few good 2-mana targets in their list, so both come out along with the situational Mathemagics.

Dimir Midrange is light on wide creature boards, so Day of Judgment and Settle the Wreckage are weak sweepers against their planeswalkers, singleton threats, and card-advantage engines. Tishana's Tidebinder is superb, countering Kaito's loyalty abilities, Floodpits Drowner's stun-lock trigger, or Enduring Curiosity's death trigger. Rest in Peace stops Enduring Curiosity from returning after it dies. Keep the countermagic suite intact since this is a slower grindy matchup where No More Lies and Three Steps Ahead answer their bombs like Kaito and Elektra.

Dimir Excruciator plays very few creatures (Superior Spider-Man, occasional Doomsday Excruciator, M.O.D.O.K.), so your sweepers are mostly dead weight and come out. Overlord of the Mistmoors comes in as a resilient threat that generates two 2/1 flying Insect tokens on entry and again on attack, giving you a steady clock and card advantage even through their discard (Duress) and removal (Bitter Triumph). Their Doomsday Excruciator library-exiling effect punishes long games, so applying pressure with Overlord while holding up countermagic like No More Lies and Three Steps Ahead is the better plan than trying to sweep a board they rarely fill.