You can’t. You can only get delivery pricing. They don’t have the basic functionality every store has had for a decade.
Go to self check-out and grab a scanner for your heavy items, which they sell many of. You can’t, they don’t have them, you have to wait for the attendant to get to you with it. (They’re generally good at their job but it’s still annoying if you’re in a rush.)
Sam’s Club is as good as it gets tech-wise, in-store and out. They even have AI that allows the exit door receipt checker to skip checking people so you don’t get stuck in a line waiting for someone to verify you paid for everything.