These tennis shoes have too much toe room. (...have plenty of toe room could mean that it is comfortable, though.)
Inside this tennis shoes, there are too much space between the big toe/the toes and the tip of the shoe.
These tennis shoes don´t just fit well, too big for me!
One tip I learned was: Get up onto the ball of the foot. Can you put your index finger between your heel and the back of the shoe? If not, the shoe is likely too small. If your finger fits too snugly, go up half a size.
So, if you could put two fingers between your heel and the back of the shoe, it would be too big for you! That is, here the method/reasoning is reversed, from the front of the shoe to its back.
Let´s wait for more answers.