Clutch fluid condition does only affects clutch operation when disengaging the clutch so that would not be part of your problem.

50k miles seems very short for clutch life if driven correctly. Typically when a clutch starts to slip it’s most noticeable in lower gears due to the greater torque multiplaction from the lower gear ratio vs higher gears/gear ratio.

Do you have any way to monitor throttle position sensor while driving? I had a bad throttle position sensor that was worn in a small percentage range (17.2-17.8 percent if I remember right) and it would read much lower in that worn area causing a stutter/shutter type feeling.