Free Gold for purchasing a Game Pass

Free with Game Pass means you can play them without purchasing the games while you have a Game Pass subscription. Once you lose the subscription, you will no longer have access to those games.

Free with Gold are Games with Gold games. You can redeem the for free, but you need a Gold subscription to continue playing them for free.

Did you actually purchase the game, or was the game "bought" as a free Game with Gold or rented during Game Pass?

If it was a Games with Gold game, you will have to have an active Gold membership, and as a Game Pass game it might have left Game Pass or you cancelled the Game Pass subscription.

Gold allows you to play online multiplayer and gives benefits such as discounts and free games with Games with Gold.

Game Pass Ultimate is a bundled subscription of Gold, Game Pass for console, and Game Pass for PC. So you get the same Gold benefits, but also both Game Pass subscriptions without having to purchase all subscriptions individually.

Minecraft and Descenders are not free games. You can play them for free if you have Xbox Game Pass or Game Pass Ultimate. An Xbox Gold subscription allows you to play multiplayer games online but does not give you access to the games without purchasing them.

To clarify #3, PS does not have a similar service. What you're thinking of their is Games with Gold. Each month you can download 4 games for free (2 360 games and 2 One games). These may be on Game Pass and they may not. The 360 games are yours to keep without
gold. The One games are only free while you have Gold. These games you would actually "purchase".

Game Pass is different in that there are 100s of games available to pick and choose from. Games are added to the Game Pass library and you can download them from there. Youcan play them as long as they are part of Game Pass or keep them if you purchase them
(you do geta discount if you buy them while javing Game Pass).