Bluetooth won't turn on my iPhone XR? Have a very odd bug--I can't turn Bluetooth on or off. This isn't at a device level--when click Bluetooth in Settings, there is just a spinning rule of death next to "Bluetooth." In the Control Center, Bluetooth is off. If I tap it, it turns on, but the Settings screen is still spinning. I also cannot tap it off in Control Center once I tap it on.

Anyone have a sense if this is a software or hardware issue? My Bluetooth was working an hour or so ago. I saw some articles suggesting this was a hardware issue but it seemed like those were mostly issues affecting iPhone 5Cs; I also saw some suggesting it was a software issue with an old iOS release from 2017, which is obviously not relevant.

I've done all the obvious things, like restart the phone, soft reset, and even reset all my network settings.

I had previously had AirPods Pro, an iPad, and Bose headphones in the saved pairings. All three were not connected. AirDrop also tells me that Bluetooth is off (even when it is "on" in Control Center).
Just to close out the answer—as Allan noted in the comment, the Bluetooth radio itself was broken.