Another game that has amazing clouds, where you move around them horizontally and vertically, is the recently released Ace Combat 8. The game itself is UE5 but clouds seem to be completely custom made, volumetric, and look amazing, especially noticeable as you're flying around/through them in the game. Examples: https://x.com/PROJECT_ACES/status/2042437413260443803 - https://www.youtube.com/watch?v=BG7DLLdQf1k

The game is even more amazing in VR where you really get a better spatial understanding of the entire sky, environment and the clouds.