Lifted carpet, found 3/4 plywood 2003 build, nails used.

There are smaller dips but at least one area goes 1/2"

Will be installing floating floor, engineered wood, Kahrs across joists, which are 16" apart.

Planning to put additional screws. Not sure how generous I should be.

Also should I place transition at closet line? I have trackless bifold doors there.

Exterior wall by the windows has air vents. Opposite side has Master bathroom door.

Kahrs manual suggest roofing felt paper for dips. I am thinking deepest dip should have Ardex FF added?