I think I may have discovered an interesting clue related to this problem. I now have 5000 miles on my 2019 Titanium and it still exhibits the same buck/surge behavior at slow speed that it did on day one. However, I was recently sitting in a long line of stop and go snail trail traffic so I decided to try out using the adaptive cruise control for it. It was pretty much working as expected, (your ride is no smoother than how the guy in front of you is starting and stopping), but then I realized I wasn't feeling any buck or surge sensation when starting out from a full stop.
So it got me thinking, what are the differences between the accelerator pedal's encoder's signal to the PCM versus the adaptive cruise control's signal to the PCM? Perhaps the latter bypasses the "adaptive learning" software which appears to be central to this issue?
Anyhow I just now called the service dept where I bought the car and got a service appointment for Jan 6th to get the TSB 19-2331 fix. Almost 2 months for a software update! It makes me wonder - if they can continuously beam down mountains of navigation data to me, why can't they beam down the software update for my transmission? A little pop-up on the screen says "You've got mail! Ford wants to reprogram your car. Press okay to continue."