welcome to the forum!
sorry you are having issues with this car.
it sounds like you have internal damage problems with the transmission itself.
if P does lock the car, and all other gears release the car, but fail to engage any drive gears, then internally, something is not working.
you could simply be low on transmission fluid, but it sounds more like b2 failure, except then Reverse would work. so I'd have the car towed to a transmission shop for evaluation.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!