ANT Colony is my Sonos One

You throw it in the ocean, then buy another One.

Gently blow it out with low pressure air, the output from a vacuum is good, canned air isn't so good as it can be very cold but if you have nothing else use it carefully and keep the can warm to minimize thermal shock.

Terro makes some great anti-ant stuff, mom's computer got infested often until I dosed outside with crystals and put out blobs of dine and die tabs inside.

Even with Stanley_4's recommendation the downside is that the Sonos One (or any Sonos speaker for that matter) isn't easily opened. If the ant infestation is as bad as you seem to describe it; the speaker may have internal circuitry damage.

That said (and I have no idea if this will work) you might place the speaker in two zip lock bags (the second acts as barrier in case ants escape the first) and then place the speaker in your refrigerator for 72 hours. Remove the speaker and let it stand for another 72 hours to gradually come back to room temperature. Caution If items tend to freeze in your refrigerator then don't place your speaker in it.

Good Luck.

Edit: There is usually a path/entry point from the outside as to where the ants travel. I'd try and locate it to spray ant repellant. Could your speaker be near a window or exterior door?

Yet another example of Sonos bugs!