Ambient sounds on HomePod mini

My HomePod mini is beside my bed and I want to use it for ambient sound to sleep. My favorite is thunderstorms. I want to ask Siri to play thunderstorms on my HomePod mini while I sleep.

When I ask, Siri starts playing tracks from Apple Music. The tracks start to have New Age music and eventually will play waterfalls, jungle sounds, ocean waves, everything except rain sounds, which always wakes me up.

I can do it manually but would prefer to just ask Siri.

Is this a case of I am not asking correctly? Is Siri assuming I am asking for music for relaxation? Is there a work around for this? I was hoping to find a solution without purchasing a noise machine.

I hope the solution is simple and doesn't cost more money.

The phrases I have tried:

"Hey Siri, play rain sounds" (plays from Apple Music)

"Hey Siri, play thunderstorm sounds" (plays from Apple Music)

"Hey Siri, play ambient rain sounds" (plays from Apple Music)

"Hey Siri, play ambient rains sounds only" (plays from Apple Music)

"Hey Siri, play ambient sounds" (does not always play rain, usually something else.)

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