Potty training: he will pee in the potty when naked only?

So my 3 year old has just started learning potty training, and doing great! When hes naked from the bottom and only wearing a shirt (no diaper, undies etc) he goes right to the potty to pee which is great! But once the pullup is on, he forgets about the potty.

Its only been 2 days of training so Im not comfortable ditching the pullups completely, so hes in pullups in daycare since he hasnt mastered the toilet in daycare and has a harder time telling them he has to go.

Is this the time most people put on undies for their kids and all the accidents happen😅? Is that what I should be doing right now?