[brazen1]

That's because your PDVD filetypes are not exclusive.  They share common filetypes with the 4K iso's you want FAB to open exclusively.  Just because you're using a filename for FAB, doesn't mean PDVD filetypes are going to be ignored.  Every PDVD rule you have is the same for a 4k iso so all of them are common.  Fwiw, FAB doesn't match refresh rates unless you manually change in GPU settings before playback and you'll need to put it back after - not ideal imo.  Also, the Kodi internal VideoPlayer handles 4k iso's with menus but read my post above yours.  So do other external players but without menus.  If you insist on using those two players, perhaps use a unique filename for "HDR" assigned to FAB and another for "SDR" assigned to PDVD but you'd have to rename all your iso's.  I'd test a few first to make sure the PCF.xml can handle two filename rules because it might not.  If it does, I'd flip the two rules one before the other and make sure that doesn't make a difference either.