Participant - no, the game pass is a bit like netflix for games... while your subscription is active you have access to all the games in the catalogue, when your subscription stops you no longer have access to any of them, whether they are installed on your computer at that point or not. Games also come and go, so a game will not necessarily always be available if the developer decides to remove it from the platform. Given this is a MS first party game I expect it's likely to remain but it's not guaranteed.
Put simply, iif you want the game forever whether you are subscribed to gamepass or not, or you want the premium versions then you need to buy the full game. If you are happy dipping your toes in with a subscription to gamepass and accept that you will lose access should you cancel that subscription at some point in the future, then gamepass is the cheapest way to try it (and of course you get access to all the other games on the service).