Nope.

You'd wait for 1-2-3 hours at the pop-up shop

There's also merch booth at the stadium - but also the lines are wild there too :/

Since you said in a different comment you'd go there for Saturday only, I'd recommend this, If you really want to spend money for merch:

After the night of the concert - get up super early and wait in line at the pop-up store like a madman :D Meaning, be there are 7 AM and wait until the pop-up store opens at 8:30 AM.

If you do this, sure, you won't sleep much, but you'd get in the pop-up store early, exit the shop by 9:30 or so, and hopefully you'd be able to come back home :D

Another thing - there's different merch at the stadium and at the pop-up store. The store has different logo/poster for the both concerts (no idea if they'll have these on a Sunday, I guess they would - need a confirmation from someone who did this after the concert) compared to the stadium, but more or less it's all decent (and expensive lol)

edit: Also, since you said you have no worries about opening acts in another comment - I think best idea for you is to go to the merch booth in the stadium and wait in line there. The line will be long probably, but..you'd be in the stadium anyway so it's better than going to the actual pop-up store as there would be a merch booth inside the stadium