A couple of things I’ve noticed regarding the warped beds
#1 it is primarily made of plastic
#2 three lead screws rather than 4
With those two things I’ve pointed out which we all already know it is of no surprise to me that many people are having issues with a warped bed
That being said when the bed screws underneath are tightened it will be extremely easy to either tighten too much, not enough, or unevenly
I would suggest using a straight edge and adjusting the thumb screws underneath that hold the plate to the Z frame
Being that the bed is primarily made of plastic it will easily go out of true if the fasteners are uneven which in turn should be able to be resolved by adjusting the tension on the thumb screws
I’m not a fan of the instructions of the Wiki page showing pictures of the bolt head flush with the thumb screw underneath and calling it good
As always this is just a suggestion which hopefully will alleviate the extreme dish in the center of the bed
If my bed was warped that’s what I would try first 