Jungle update could include Jungle villages, Waterfalls, Improve temples, add throwable spears, Some type of primate animal, and maybe even Bananas think about it.
We may get these in the Caves and Cliffs update, since mountains are about to get a big improvement in terms of terrain generation. I doubt goats and increased height is all we're getting. I too would love to see a mountain jungle hybrid biome, perhaps we could have a new neutral mob called gorilla, which like the polar bear, is non hostile unless players get too close to their babies, then they attack, or if players fail to go away in time when a silver back beats their chest in front of them which is a warning, the warning should be 5 - 10 seconds, if the player remains within 16 blocks of them still, they're in trouble.
However if the player feeds the gorillas bananas, they are tamed and can be bred and will defend the player against Zombies, Skeletons, Zombified Piglin and Pillagers.
There are lot of suggestions here about jungle update.
Piranhas in jungle rivers, jelly fish in warm ocean, gorillaz, purple orchid to obtain purple dye
Piranhas in jungle river idea I like, and players should be required to be wearing Thorns enchanted armour to safely approach them, because the piranhas would swarm in such high numbers toward the player an effective defence would be Thorns, without it, the piranhas will not die off quickly enough for players to survive with more than half of their health remaining.
This means water will now have 3 hostile mob types, only two of them existing in jungle biomes and that is Drowned Zombies and Piranhas.
Regular lakes could be updated to have pikes, but they would mostly ignore players because pikes aren't as aggressive against large animals as piranhas are.
Swamps could be updated to have crocodiles someday, forcing players to use boats, tridents, elytra, ender pearl or frost walker enchanted boots to safely get across, as going in without any armour would likely end in catastrophe for the player.