Heroic Boon: Ritual Caster or Magical Secrets. I don't think it would break anything to add swift ritual to the ritual caster option. Being able to take rituals from other spell lists is cool but casting rituals as an action is cooler.
I dont know I thematically can get there, especially when you are unlimited on the rituals in your spellbook, I think the wizard is a bit underwhelming. I might tinker with an idea centered around action economy, like that they could cast 2 circle spells provided they have the action, or maybe even give them like a PB/LR or similar bonus to spell potency(damage or duration)
