The simplest tasks on iPadOS are either incredibly difficult and time-consuming, or they’re so unintuitive that even a 25-year Apple veteran can't figure them out. Frankly, neither reflects well on iPadOS.
@snazzyq Yes, it’s too complicated. However, you almost got it: on the external display, when you tap the 3 dots and select ‘Add Another Window’, you tap on the Freeform icon and you’ll get your second window, which you then can move to the iPad. Hth!