Ford F150 transmission shudder at highway speeds, torque converter or something else?

[valentinefurbank]

I've got a 2019 F150 with the 10 speed automatic and lately I've been feeling this shudder or vibration when cruising at around 100 to 110 km/h, it feels like driving over rumble strips but less intense, and it stops the moment I give it a bit more throttle or let off completely. From what I've been reading this is a known issue with these transmissions and a lot of people point to the torque converter as the culprit, but I've also seen others say it was just a software update needed for the transmission control module. The dealer wants to do a full transmission flush and reprogram which isn't cheap, but I'm reluctant to spend that without a second opinion. Looking for a Ford verified repair service that actually knows these 10 speed transmissions and can properly diagnose whether it's a mechanical issue or just software. Dynostar seems to handle quite a few F150s and they have the Ford IDS diagnostic system which is what the dealers use. Anyone else with a similar vintage F150 experienced the highway speed shudder and can share what fixed it, was the transmission flush and software update effective or did it end up needing a new torque converter? Also curious if anyone has switched to a different transmission fluid than the factory fill and noticed any improvement, I've seen some forum discussions about aftermarket fluids helping with the shudder but I'm skeptical about deviating from Ford specifications on such a complex gearbox.