Having a dozen grand kids I have had all kinds of damage done to our screen doors. When the door is out of square and no longer closes it’s time to get a roll of screen fabric or mesh for your door size.
Pop the door out and lay it down (screen side up) in a flat area it looks like your patio would work.
Look around the permitter and find the place the screen clamp/cord is split and using a screwdriver or a fork pry 1 end out and gently pull the cord out.
Remove the screen and save for a smaller window or toss.
Now the important part the frame needs to be square.
Measure diagonally bottom left to top right
Measure diagonally bottom right to top left
We need to adjust the frame so both measurements are the same this is the part that is important getting the frame square (do not try your use a square measure corner to corner).
Once the frame is adjusted to square, unroll the new screen on top of the frame.
I try to make sure the lines are running straight on the screen to the door it makes installing the clamp cord easier.
I install the cord along 1 side and again check that the frame is square. Don’t trim screen until done.
Go to the opposite side and pull any wrinkles out of the fabric or mesh.
As you start securing the opposite side the screen gets tight if not pull the cord and try again with the fabric slightly tighter.
Once you have 2 sides and your frame is still square put the cord in the 3rd side, then making sure all wrinkles are out attack the cord on the last side this really tightens the screen and hopefully the frame is still square!
Replace the screen door in the track and it should fit properly.
The first few times t tried to go around but got wrinkles. I found doing opposite sides was best for me.
Some screens come with new lock cord I use whatever fits best sometimes a bit of both.
I can not tell you the number of times I have done this my last home had 4 sliders and the grandkids were mostly younger between dogs and kids I was regularly doing this. They make a roller to put the cord in I have a couple but one of my wife’s wooden spoons works just as well for me to press on the cord.
Give this a try it will square up the door and won’t take long plus it will save $.