If I cancel my Gamepass subscription do I lose my downloaded games?

If you bought them while you had Game Pass, they're yours to keep. If you did not buy them, you would not be able to play them without a Game Pass subscription.

My net speed is 3mb. I spend days to download one single game. Which means, I lose days from my GamePass subscription for download only. This not fair!!

If you're on Xbox One, click the Xbox button, hiver over to your profile pic, click a and hover down to my subscriptions. After looking at your subscriptions, you can see if you are accidentally still subscribed to Xbox Live Gold or Gamepass. If you want
to cancel it, click on the subscription, pick the option to manage and then hover down to the bottom of the page to find a link to cancel if you don't want it.

Just remember that you can lose access to some games from your library if you cancel GamePass and lose access to online features if you cancel Live.

Do you have a base Gamepass or a Gamepass Ultimate subscritpion?

Because there is a huge difference... if you have the base gamepass you can definetly have a separate gold subscritpion, I had this situation in the past.

But if you have the gamepass ultimate the situation is different since all the other subscriptions are absorbed by the ultimate.

In general if you cancel a subscription you will immediately lose all the benefits, for example if you cancel the gamepass you will not be able to play any gamepass game immediately.

If you only cancel the recurring billing you will maintein all the beniefist up to the point it has been paid to.

If you purchase Gamepass you will have access to download and play any of the titles in the gamepass library while you are a subscriber. If you cancel or let the subscription expire, you will lose access to those games. You will not own them.

https://www.xbox.com/en-us/xbox-game-pass/games