What is the difference between "taper le ballon" and "tapper dans le ballon"? Is the kick in the latter stronger? That is what I understood from https://www.larousse.fr/dictionnaires/francais/taper/76648 , but I am not sure.
The correct form is "taper dans le ballon" and mean beating a ball or kicking it in a football match for example. For example, "Le joueur a tapé dans le ballon de toutes ses forces" or "Il a tapé dans le ballon pour ne pas le prendre en pleine tête" are correct uses of the expression.
We informally use "taper le ballon" mostly to propose a football play with friends for example. We can also use the term "balle" which simply means ball. For example, we can say things like "Viens taper le ballon" or "On fait un match histoire de taper la balle ?" In these examples, you can also replace "taper" by "toucher" which means "touch". The sentence "On fait un match histoire de toucher la balle ?" is also fully understandable.
The former would be more like 'beating up the ball', which makes little sense (except if it's colloquial and means 'stealing', but that's not your question). 'Taper dans le ballon' is the normal way of putting it (generally for 'kicking').