I’ve had sliding patio doors in which won’t open

There is really not enough info , you have the handle apart ok is this a problem or have the wheels worn and need to be adjusted. Sliders usually have 2 wheels that are adjusted with a screwdriver or Allen wrench. The problem I normally see is the wear on the wheel and track causes the latch to be below the catch point. On some doors I have had to replace the assembly not hard but the door has to be removed then take it to the store to match it up with a replacement. I know the big box stores used to carry several models if yours is worn out, but adjustment will probably do the trick.

I was presented with a case where someone over-tightened the screw adjustable post that the locking slider slides down on. He then forced the slider down and it was pinched so tight that he could not get it back up.

I pushed the door closed as hard as I could and could then move the slider up so it came free. You may be able to apply force to the door toward the lock and manipulate the slider up with a screw driver inserted through the hole left by the parts you removed. It might help to spray or squirt lubricant onto the slider.