I am renewing the fixtures on a 2nd floor bathtub with no easy access to the area beneath the tub drain. The present setup has a toggle fitting at the overfloor to open/close the drain. This has never worked very well. I would like to replace it with a simple one where you pull up a knob right at the drain itself. I am wondering if there are any retrofit type drain screens that work this way such that you don't have to remove the threaded drain flange itself. I can remove the top screen but I hesitate trying to remove the flange.

Bathtub retrofit drain device