The only way to do this normally is to allow Marik to Summon Ra and destroy it (or somehow discard it from the hand), then Special Summon it from the graveyard
Lunala 227 Marowak Fighting 100 Bone Beatdown (40) Lunala 228 Jigglypuff Colorless 60 Rollout (20) Solgaleo 229 Wigglytuff Colorless 100 Genlte Slap (50) Comforting Song (Ability) Once during your turn, you may heal 20 damage from your active Pokmon
Since Sagas are among the enchantments most likely to wind up in the graveyard, that seems like a good fit for the playstyle of the Enduring Enchantments precon
Then, when your opponent board clears you, pump all that mana into Defenders of Humanity again
This isnt always a huge problem, but can certainly impact things when you wanna cast Eris, but you just emptied your graveyard with Dig Through Time
These proxies are especially useful for Commander players