The DLC Skin pack requires the base game to use, Destiny 2 is Free to play: (Alternatively you can just add the base game and it auto adds the DLC Skinpack)...
Also Shop Titans which looks to be a mobile port microtransaction hell game, I'm not going to post a trailer or anything on it as I don't support that kind of garbage.
Link works correctly for me as of this moment, sometimes I do have issues with EGS links and my VPN filtering it also sometimes EGS will modify store pages for freebies causing a broken link for a little bit which we've seen a couple of times.
You didn't read the GoG newsletter obviously :p
It's also always been hidden in plain site at the bottom of the page(s) on GoG, I found out about it last year from a newsletter and then just started noticing the link everywhere.