Then it is highly unlikely you have a transmission problem, you have an engine power problem.

That said, if the torque converter stator sprag is seized, you could have a limited top road speed however that isn't likely given:

1) You are struggling to get a 1 - 2 - 3 shift. A seized sprag would allow goodish acceleration at lower road speeds since loads are low.

2) There would be a loud whistling noise from the torque converter.

3) Trans temps would be very high triggering overload codes.

4) That evil limp mode specifically designed to take advantage of the motoring public even though there is noting wrong with the car would kick in. ( Well according to a thread in the tech section )

On the other end of this, if the stator sprag was free wheeling, acceleration would be slow but top speed unaffected and there would be no noise.