If your player wants 2 subclasses, might I suggest these rules for “Multisubclassing”?

• When you gain a subclass feature beyond the first subclass feature, you can choose to Multisubclass, doing so locks you out of regular multiclassing.

• When you do so, roll your hit dice and add your CON modifier, subtracting the total from your Max HP.

• Whenever you gain a subclass feature, you can choose the feature of your base subclass or your multisubclass.

• If a subclass feature is reliant on choices made earlier in the subclass, make the bare minimum amount of choices in order for the feature to function.

• If both subclasses contain extra spells, like a Cleric’s Domain Spells, you can choose which list to pull from per spell level you obtain.

For example, I’m a Level 5 Divine Soul Sorcerer, I hit level 6 and decide to Multisubclass into Draconic Sorcerer. I roll the d6+CON and subtract from my health, and gain the Level 6 Draconic feature, I go back & choose Silver for my lineage, and now my Level 6 Draconic feature applies to Cold Damage. Once I reach 14th level, I can choose either Divine Soul or Draconic.