So everyone knows that HITMAN 3 first appeared on epic games and after a while ,on steam too
By the time i got across this game and got myself to like it, i was playing it from Epic,starting with the demo
Then ,I found myself buying The first HITMAN game,from a key selling site, there were no issues at first ,the developers thought about the possible cross platform and added an account linking feature,allowing players to keep their progress through out the whole trilogy
And so I linked,my steam account with the epic account,having access to play the first game missions on a DEMO!
Later i bought more and more DLCS until i had almost the whole game bought ,this means i ended up buying the HITMAN 3 game from Epic(since at that time it was not on steam)
And so far, i was playing the whole game and some DLCS from Epic(Note: the only game linked from steam to Epic was just HITMAN,the rest of the game was bought on Epic)
Now this is the most interesting part,i decided to go grab myself some more DLCS from those key selling sites,so i did,then i came to redeem them and i got a error,saying i cant add DLCS to a game i don't own(Note again:i had only linked the first HITMAN game to my Epic,so i was indeed, NOT owning the base game)
So i said "that makes sense" and thought to myself "what if i go install the demo from HITMAN 3,and do the same thing i did with Epic(get the demo from steam ,a somewhat "base game") and THEN add the DLCS"
Guess what...It didn't work...So now I'm writing this ,to understand why i can use Epic demo to link accounts and even play the game,but can't use the Steam demo ,just to add three DLCS...
Now i don't want to buy the game on steam too, just because i bought three DLCS cheaper...

Hope i managed to make the issue clear,it's late and i have work tomorrow,So, i hope it's understandable