I think that it would be cool to have a category in which you have to complete the game a set amount of times for example 3 or 5. This would require more skill than the 0.1 seconds it takes to complete one run for easy mode.

As RNG plays a significant role in the top runs, I think something like this would be nice. A category like this would definitely rely on less luck than the other categories

I agree, seems like a good way of testing the skill. Kinda similar to how rubik's cube records are done.

I like the idea, but this should be in category extensions, not in the main google minesweeper category.
But you can try the 100% category which is similar, you have to complete a hard, medium and easy run as fast as possible in the order you want.

That is a cool idea, we might consider it for a category extension in the future (like Gbasire said), but there hasn't really been any demand for it at the moment.