Please could a native help me with these sentences?

Could you please tell me if these are natural, if not how you would say them please?

1 I can't even watch the video with the quality this bad. The internet connection is too slow to watch any streaming video.

2 Why couldn't I have won this one time? I had to lose. Why was I unlucky on this game and not that one?

3 The hotels that weren't 4 stars are now 4 stars.

4 That number was too high for it to be correct.

5 I'm 100% sure I'll win without having to do that.

6 I don't remember anything I learnt.

7 Could you leave it as it was when you got here?

Thank you