The easiest way to do this is just take however many slots you would normally fill with two-cost mana rocks, and replace them with two-cost Merfolk Looter (and other creatures with similar draw-discard activated abilities)
Concealed Courtyard, Spirebluff Canal, Blooming Marsh, Inspiring Vantage and Botanical Sanctum reprint MTGs offering of enemy fast lands - land cards that can be tapped for either of two mana colours, but enter the battlefield tapped unless you control two or fewer other lands
Modern Horizons 3 Commander Decklists Four new Commander decks (and Collector's Edition Commander decks) will hit stores when Modern Horizons 3 releases June 14, 2024
Upgrading Spirit Squadron As Ive mentioned already, the deck is fine as is, and plays as well as you would expect from a preconstructed deck
If so, it might be a good idea to cast a boardwipe