Cast Miirym either from your hand or from the command zone by paying 3 plus commander tax, if applicable.
Reflections of Littjara triggers, copying the Miirym spell, creating two token copies of Miirym.
Put all but one legendary Miirym into your graveyard due to the legend rule.
When the Miirym tokens enter, Ganax triggers twice, creating four Treasure tokens.
Resolve the original Miirym spell. Choose to put the nontoken Miirym into your graveyard due to the legend rule.
Each Miirym you control and Ganax trigger,
Resolve the Ganax trigger, creating two Treasure tokens.
Resolve a Miirym trigger, creating two token copies of Miirym that aren't legendary.
When the Miirym tokens enter, Ganax triggers, creating two Treasure tokens.
Repeat from step 8 for each remaining trigger, if applicable.
Activate a Treasure by tapping and sacrificing it, adding one mana of any color.
Repeat step 11 until you control no Treasures and/or you have enough mana to cast Miirym from the command zone.
Repeat from step 1.
This dazzling dragon-storm begins when you cast Miirym, Sentinel Wyrm, whose legendary status is smoothly bypassed by Reflections of Littjara copying the spell into multiple non-legendary token copies. The moment these dragons flood the board, Ganax, Astral Hunter triggers repeatedly to generate an overwhelming horde of Treasure tokens, heavily amplified by Elspeth, Storm Slayer doubling every single token you create. By sacrificing those abundant Treasures for mana, you secure the endless resources needed to recast Miirym from the command zone over and over, compounding your triggers into an infinite spectacle of tokens and colored mana.