S26 from amazon for tmobile

I have an s22 and I'd like to upgrade. I am on tmobile. Is there an down side to buying from Amazon and bringing it in to swap in? I hesitate to buy things from Amazon with quality control concern for knock offs... but the extra memory and gift card is enticing. I've always gotten phones from either the carrier or best buy when they were linked.

I dont want to trade in my phone. Can pay outright.