Transmission Fluid Service - Question

Hey folks! I was looking into getting a standard fluid service done on my Mustang GT (2021 10r80 5.0) sitting at 80k KM (50k Freedom Units) but I’ve gotten two different answers as to what service is being done at my local Ford Dealership.

They tell me they either do a Flush (400$ CAD) or they drop the pan and give you a new filter and gasket. (650$ CAD) Which one is the preferred method?

I’ve heard both sides about both and I’m wondering what’s the better route to go?

My main concern is a flush doesn’t change the filter or gasket but with dropping the pan there will still be a good chunk of ATF in the TQ converter. I drive my car decently hard but I definitely do not live in the upper Tach, just the odd hard pull and downshifts.

Am I being paranoid about this leftover fluid in the TQ converter?

Any help or advice would be amazing, thanks friends!