/locatebiome command doesn't consistently locate the nearest cave biome

As we know, /locatebiome command doesn't specify y-value, which is intended (see MC-206286). However, the command doesn't correctly find the new introduced cave biomes (as they are 3D biomes distributed underground). This doesn't happen with the regular surface biomes.

This leads to a number of issues where the command doesn't search accurately for the nearest biome when the player is on different height levels, and is inconsistent with how /locate works, as that command successfully finds a structure independent of your Y position.

Note that this report is not implying the command should specify the Y coordinate, but to locate the nearest biome regardless of your Y position. Similar to /locate.

Expected result

/locatebiome command would find the nearest biome, regardless of the player's Y-position, like how /locate works.

Observed result

The command doesn't always find the nearest 3D biome, instead it searches horizontally depending of the Y-level the player is at, leading to situations where the command locates the biome very far away or can't locate it at all.

How to reproduce

1. Create a world, search for a lush caves or dripstone caves biomes on your current level.
2. Now fly to a really high Y-level (i.e. above 180) and search again.
3. On most cases, the command locates a different cave biome, or is unable to locate one.