Canvas isn't scaled properly on mobile

Hey guys, I’m developing a mobile game and I have an issue with the Canvas scaling not appropriately…
When using it with GUI’s that aren’t levels, like main menu, settings etc. I use Render Mode: Screen Space - Camera. And UI Scale Mode: Scale with Screen Size. Which works brilliant.

The problem is when I enter the game itself, when I created a canvas and used Render Mode: World Space.

But now when I’m using Canvas for buttons, panels, etc… resizing the Canvas to fit the Camera, it won’t fit the mobile screen appropriately. So I switched to Screen Space - Camera which gave me other problems, now all the objects have to be scaled. meaning objects that their size was 0.25 is now like 25. objects that were 50 are now 220. speed is now 1200 instead of 12. What should I do?

Do you solved it?