BxOnOff

Turn screen on/off with physical button if the button can be remapped to invoke this App. Here is the step for Galaxy S10 as example::
(1) Open the App first time.
(2) Click "Screen On/Off Setting"
(3) "Activate device admin app" menu opens
(4) Click "Activate" at the bottom-right.
close the app.
(5) Open "Setting" -> "Advanced features" "Bixby key"
(6) Choose "BixbiScreenOnOff"
close the setting