Hi look like everyone want to land in gas giants I have idea that I have thought for 10 minutes
First Layer : will be the hydrogen blocks that you can pass through , I suggest that player land on jupiter with parachute and then he will pass through 20 to 30 blocks of hydrogen until he reach the second layer.
Second Layer : will be Liquid Hydrogen with white color similar to 4Space Europa Water , and for sure you need some potions and enchantments to get down to the 3rd Layer
Third Layer : the Core of Jupiter , maybe bedrock with some ores and also sure water breathing potion
thats all I hope you like my suggestion, the next topic will be about Saturn and third about Neptune and Uranus