Pre facelift 5 speed up shifts too early bogging engine down

When light-normal acceleration from 0-50mph my car will go though all the gears normally except the 4-5 shift, at 20-30mph it will shift to 5th gear too early, bogging engine down and then downshift back to 4th gear because of low power and then eventually shift back to 5th gear, it’s so annoying.

My thinking is it might be ECU but these 01-03 pre facelift 5 speeds don’t have the ECU issues that the facelift ones do, but idk. The car shifts fine and if u manually shift through it, it’s smooth.

Fuel trims on both banks and both LTFT and STFT are 1-4%

2002 LS 430 with 202k miles, did 3 drain and fills already