Hi,

sometimes I forget on which Platform I own a game. So I go to Galaxy and search for the game. Problem is if I own the game on multiple platforms, on the page of the game it only shows one of the libraries.
If I filter for a platform (e.g. Playstation) and hover over a game it shows all the platforms where i own it.
So it seems the Galaxy Client knows it, but doesnt show it on a games store page.
Not sure if it always has been like this

Take a look at your first screenshot (the Batman one). At the top, left of Overview is a box icon with a number. Click it. It lets you select which platform you want to launch the game on along with info specific to that platform. Obviously you can only launch the game on a PC, but you'll get the idea.

OHH I never noticed, my bad. Thank you!!

No sweat.
I more or less stumbled on it by accident when one of my multi-platform titles refused to show my PC info amd insisted on sticking to my PS4 info instead. I find it to be a pretty useful feature, Prevents multiple library entries.