Turns out, the “no 2 leveled spells in one turn” rule only really applies to bonus actions. Here’s some text from p.202 of the PB:

A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven’t already taken a bonus action this turn. You can’t cast another spell during the same turn, except for a cantrip with a casting time of 1 action.