The default creative mode music is Taswell, Biome Fest, Blind Spots, Dreiton, Aria Math, Haunt Muskie, and Floating Dream. Normally the game cycles through all these musics.

I go to a beach biome, and open up the music config, and add the song Ward to the beach biome.

Now the expected behavior is that the song Ward should play when I am in a beach biome. But that is not what happens. Instead, the game just cycles through the creative mode music. This can be quickly tested by using the "next music" hotkey until the pattern repeats many times. You can also look at the last played music list to see which musics have been playing. As you can see, only the creative music has played and the song Ward has not played at all.

I tried to see if the beach music could play at all, by removing the creative music altogether.

Now, the game falls back to the "game" music, which consists of Comforting Memories, Haggstrom, Left to Bloom, Minecraft, Clark, Living Mice, Dry Hands, Oxygene, One More Day, Wet Hands, Mice on Venus, Key, Subwoofer Lullaby, Danny, Sweden, and Floating Dream. Yet again, the song Ward doesn't play at all despite me being in a beach biome.

I attempt to fix the issue by removing all "game" music, so that way the only song available to be played is the song Ward.

And to my dismay, the message that I receive is "Now Playing: meta:missing_sound."

What this means is that the biome-specific music feature is not working at all. The game isn't acknowledging the biome-specific music, and only looks at the creative and game music lists when deciding what music to play. At least, this is how it is in the overworld. I did test this in the Nether and biome-specific music seems to work perfectly, probably because there is no creative and game music in the Nether.

Hello, thanks for the report.
It does work, but for now in creative you get only creative music. I may add an option to use biome specific music in the next update if you're interested =)

It doesn't work in survival either. By default, the "game" music plays. Here I've set the game music to include only the song "Minecraft."

I add a custom song, "Gerudo Valley" to the desert biome, then I go to a desert biome.

If I cycle through the music with the "Next Music" hotkey, then only "Minecraft" plays.

Now I remove the song "Minecraft" from the "Game" music, so that there is no "game" music.

Now the expected behavior is that the game should play the biome-specific music for the current biome. But instead, this happens:

How do I get the biome-specific music to play?

By the way I am using beta 1.19.3

Make sure you're in a desert, please check with F3. Also, you should have your config saved and loaded via the resource pack.
I'm gonna do some more testing but the expected behavior worked for me until now. If it still doesn't work for you, please give me more detailed steps to reproduce.
Also, you should not empty Game event as it's the music that will play if some biome is not properly set.

[EDIT] It seems that it doesn't work in 1.19.3 you're right. I will check what's wrong and post a fix

In the last screenshot if you look closely in the top left you can see the info lines from MiniHUD (basically the f3 screen but compressed) that I'm in a desert. I tested it in a superflat world where the entire world is one biome which is desert.

I didn't do anything about it for now, I got stuck with the 1.19.3 issue. I will do this right after.

@charlyb01 any new on this issue?
thanks in advance <3