Depends on the putty materials. Usually filler putty is just for filling any small holes or cracks, it's not meant to repair, it's just for anesthetics purposes. No strength

White cement is well white colored cement. If mixed with water with proper water cement ratio, it will be as strong as normal cement cube. You can even mix with clean sand to make mortar and gravel to make concrete just like a regular grey cement.

different function.
putty filler as the name implies are used more as a filler to fill the gaps.
where white cement usually people used when they want to make the wall texture to be smooth, it need a lot of work cause you need to do alot of skimming after applying it

plasterboard for partition/office wall?i always use flaxi brand stopping compound..can be use on gypsum partition n plaster ceiling..go to plaster ceiling shop they sell 1kg/pack..the tricky part is to mix the compound n water..

i think PYE is for skimming on cemented wall and those flaxi for partition/plaster ceiling board..i think diff material as those pye if already harden u can soften it back using water if not mistaken..flaxi cannot.