I assume truck has well under 150k miles so clutch being worn out is unlikely?
Reads like clutch disc is still getting some spin pressure from flywheel.
Clutch disc is directly connected to transmission's input shaft.
Wheels are directly connected to trans output shaft
In order to change gears, input and output shafts have to be matched in rotation(speed)
At 0mph output is not spinning at all, so to put trans in 1st gear input shaft has to stop spinning completely.
When you push the clutch pedal in the slave cylinder pushes in on the pressure plate springs, these springs were holding the clutch disc against the flywheel, which is spinning at engine RPM.
Once pressure plate is no longer pushing in, the clutch disc(and input shaft) can slow down and match the spin of the output shaft, even if it is 0 spin.
If slave is not pushing in on the pressure plate springs enough(reduced travel) then flywheel spin can keep clutch disc(and input shaft) spinning, this spin can often be overcome by pushing on the shifter harder than usual, as this pushes syncro gear against output shaft gears, slowing input shaft speed, but it can also cause grinding when shaft speeds are not exactly matched.
Rangers come with self adjusting pressure plate, this means the pedal's disengage/engage point should not move as the clutch disc wears down.
Your description of pedal disengage/engage moving means you have a mechanical issue.
The full travel in the master cylinder is not being transferred to the slave cylinder.
Could be air in the system, but unlikely if reservoir was full, it is free to check this though, so that would be my first stop, eliminate the obvious and bleed the system.
Yes, check pedal's pivot point for looseness, and pushrod.
Push pedal in with your hand while watching pushrod, pivot point and feeling pressure on pedal, if there is little pressure at the start you could have some air in the top of the master, this reduces travel in the slave so you don't get full release of clutch disc