In the latest 1.20.30.24 preview, the entering/exiting water sound was added. However, instead of matching the Java Edition implementation and playing for players submerging their heads, it simply replaced the previous splash sounds, which means it also gets played in all the following situations:
Entering shallow water (even the lowest heights of flowing water)
Floating on the water surface (holding jump/ascend).
Throwing/dropping items onto water.
Mobs landing and splashing onto water.
Fishing.
In this case, the potential solution is to add the splashing sound back to that kind of situation, while keeping the new entering/exiting water sound and only playing it when the player's eye level enters or exits the water.
I hate this new sound effect so much, too damn loud.