Does Barbarian rage prevent concentration on the Favored Foe feature from Tasha’s?

Rune Knight: does Giants Might’s growth effect follow the same formula as Enlarge/Reduce?

If a Wild Magic Barbarian uses their ability to restore a spell slot to a warlock, does it only work if they can hit the warlock’s only spell slot level on the d3?

“Tooth of Dahlver-Nar” for Tasha’s Cauldron of Everything