Thermokarst is dead against a deck with 17 Islands and no nonbasic lands worth blowing up, so trim it for the extra Naturalize copies to blow up Phyrexian Dreadnought before it can attack, since Swords to Plowshares also exiles it cleanly. Sphere of Resistance is excellent here, taxing their dense counterspell and cantrip suite (Opt, Portent, Stifle, Counterspell, Foil, Daze) and making it much harder to protect the Dreadnought on curve. Keep Wasteland and Rishadan Port in to pressure their mana and slow Gush/land-based value. Prioritize removal on Dreadnought over racing, since it kills in two swings.

Aura of Silence is excellent here: it taxes their artifact and enchantment spells (Opalescence, Parallax Wave, Attunement, Decree of Silence), and it can be sacrificed to destroy a resolved Opalescence or Parallax Wave before it locks you out. Replenish is a sorcery, so Aura of Silence does not tax it; use Sphere of Resistance for that. Sphere of Law stays in the sideboard, since it only affects red sources and they have none. Thermokarst is weak since their manabase (Adarkar Wastes, Ancient Tomb, Flooded Strand, Skycloud Expanse) isn't a critical choke point compared to disrupting their combo pieces directly. Keep Naturalize as additional answers to their enchantments. Keep Swords to Plowshares to answer any Opalescence-animated enchantment creatures and Sphere of Resistance to tax their Replenish/Attunement/Opalescence curve.

This is a mirror-ish land-destruction matchup built around Armageddon, so Aura of Silence is valuable as a proactive tax on their artifacts (Mox Diamond) while giving you a way to blow up an Armageddon-adjacent enchantment or stray artifact later; it is a strict upgrade over the one-shot Naturalize for the same role. Sphere of Law blunts their one Pyroclasm and one Earthquake by preventing 2 damage per instance from those red sources, which can save your Treetop Village or a creature from a sweep. Your own Terravore and Wasteland plan is already strong against their land-heavy build, so keep the core engine intact. Watch their timing on Armageddon and try to hold Mox Diamond-based mana advantage through it.