You probably noticed if your hearing is sensitive musically that some pianist sounds angry when they play loud. The piano is producing very harsh sounds when it sounds like angry. But when other great pianist plays loudly, it sounds loud but not angry.
Some beginners and piano practitioners at the early stage tend to think playing the piano loud means they need to press the keys harder. That's actually not true. Yes, you can create loud tones. But it's going to create ugly angry, harsh tones.
The difference between loud and soft on the piano is due to how high your fingers are above the keys and how close your fingers are to the keys. Because there is gravity, if you let go, your fingers (and your hand and arm for that matter) will just go down without your effort. If you drop something, any object from higher, the impact is stronger when it lands on somewhere. The same applies to piano playing also. That means, to play louder, instead of going DOWN harder on the keys, it's better to go UP higher before going down on the keys. If you need to play softer, you only go up a little bit off the key to drop back down.
Getting off the keys, slightly higher than the surface of the keys or a lot higher than the keys (depending on what you are trying to express), becomes very important. The UP movement becomes more critical than DOWN movement at least before you go down. It's because if you are not up, it doesn't give you leverage or space for creating precise control. So, create a space for you so that you can create loud and soft volumes and different colors of tones. Those tones you are trying to express are created actually before you even land on the keys. That space holds your intention. It prepares for your expressions before you hit the keys. So, do not always touch every possible key with all ten fingers all the time to play loud by pressing the keys hard just from the surface of the keys. It'll create a very harsh sound. But if you meant to create that harsh sound, you can do it that way. But I don't think you always mean to express music that way. So, I encourage everyone to go up higher than the keys and go down in many different ways. You'll notice that space will give you the opportunity for a variety of tones and volume.