GenlyAi: I don't play PUBG, but will try to get more info to help...
Do both versions come from the same launcher ("store")? Does this 'lite' version have their own 'page' on that launcher ("store")? Can this 'lite' version be considered an addon or DLC, even if it can be launched independently? If yes to the last question, there's a known bug about it. If you can, I suggest you go to settings -> 'report issue' at any rate. I can help you through it if you want.
Karolis_Babarskas: it's a seperate game with its own launcher, you can download it through their site and the launcher is currently being used just for one game - PUBG Lite. I think they must add it to their global search since there are very little known games already and there isn't PUBG Lite. But I'd like to launch it from GOG galaxy 2.0 these days, I hate the wait. Thanks for your help, maybe there is solution?
If it is not in the "Add manually" database, then I am afraid you will have to write it manually.
Go to "Add a Game Manually" in the menu, then look up ANY game that you won't be playing, at random. For example, "Bad Rats."
Mark Bad Rats as "Owned" and it will be added to your library.
Now, click on it to enter its game page and from the top you will have the option to "Edit..." the game, including its cover, title, and other information.
Replace this information with PUBG Lite's (including its cover art and header) and that's it. Once you're done, click on "Link Executable."
It's the closest you can get without the game being in the IGDB or GOG databases. All of these changes, including your custom cover, are saved to the cloud, so even if you reinstall Galaxy or switch to a different PC, Bad Rats will be replaced in your database by PUBG Lite.
For everybody else, Bad Rats will still appear as Bad Rats. For you it will be PUBG lite until they add a proper entry in the GOG database.