Trying to sort out upgrade options

Hi all,

I have a question that my local store could not sort out...

I have a paid off iPhone 14 Pro that I want to replace on my AT&T Unlimited Your Way account with a Galaxy Fold5 and I want to find the best way to do this. 

2 main things I want to accomplish:

1) I would prefer to buy it directly from Samsung as I have some credits and can get my trade-in as a lump sum if I go unlocked.

2) I do not want to be locked into a 36-month AT&T installment plan in case I want to upgrade yearly or more often.

Probably the "easiest" way is to buy an unlocked phone from Samsung and just activate it on my existing AT&T line (where the iPhone 14 is now).  Trade-in existing phone through Samsung.  Are there any downsides to this?

The other approach is to obviously buy it through Samsung with AT&T as the chosen carrier and choose lump sum payout, and then deal with returning it through AT&T. This makes me a bit nervous given the complaints about this process (though most seem to be in regards to the bill credits).

I'm probably just splitting hairs, but have been vacillating over this iPhone -> Galaxy swap for months and just want to finally decide.

Thanks for any advice and particularly any potential pitfalls ....

JT