Sport shift does not work.

First thing to check would be the trans oil level
To little oil will cause it not to shift
And worse case the torque converter needs replacement

can try a filter change but issue can be in the valve unit --pump --or simply worn clutch packs

The TAP Shift system allows the driver to manually shift gears by using the TAP Shift switches located on the Automatic Transmission Shifter. Pushing the Up switch will command an upshift and pushing the Down switch will command a downshift. The TAP Shift system is activated when the gear selector is in the Low (L) position and is deactivated in all other positions.
If the PCM detects an invalid voltage on the TAP up/TAP down switch signal circuit, then DTC P0826 sets. DTC P0826 is a type C DTC.

High or Low Upshift or Downshift Speed

High or Low Upshift or Downshift Speed
Checks

Cause

DEFINITION: An upshift or a downshift (or TCC apply) that occurs at a speed outside of the calibrated range. Refer to Shift Speed

ECM/PCM calibration information

Incorrect calibration in the ECM/PCM

Throttle position (TP) sensor

Misadjusted or faulty TP sensor

Check the transmission computer

when in auto shift mode you place gear selector in auto shift and as you drive you are in control of upshifting and down shifting, when you want to shift up you slide shifter to the right and to down shift you slide shifter to the left, but also know that the vehicle will up shift on its own if rps are to high and will not downshift all the way back to first, and try not to take off in higher gears that nwill burn the transmission

Hard downshift on that tranny ? means either your downshift cable is out of adjustment? or the shift solenoid shift pack has a faulty solenoid and or sticking servo valve or loss of voltage

Hello! TapShift is very easy to use. First you have to put the console shifter in "M", at that point you are disengaging the automatic shifting in the transmission. If you're at a stop, the TapShift will default to 1st gear, if you're driving, it will determine the current gear and assume it. To shift using the paddles, you push them forward to upshift, and pull back to downshift. You can use either paddle individually, or together.

Hope this helps and thanks for using FixYa!

Cheapest thing to try is a fluid flush and filter change. Unfortunately, if that does not work, then next bet is probably a rebuild.