Phone calls try to connect to Bluetooth speaker even when Bluetooth is off

I've been using my soundbar to play my iPhone 13's music through Bluetooth from time to time. I turn Bluetooth off when I'm not connected to the soundbar, because in my experience Bluetooth can cause a lot of unintended problems.

However, when I receive or make calls and try to use speaker, I get a selection window. The phone is trying to decide whether I want speaker or to cast the call to the soundbar. But Bluetooth is off, so even if I selected the soundbar it presumably wouldn't be successful.

Why does the phone even give me this option when Bluetooth is off? It's very frustrating when every time I answer or make a phone call, I have to hit an additional button just to use speaker mode. Especially when receiving calls, because I have to leave the caller in silence for several seconds while I try to get speaker activated.

The simple solution (seemingly) would be to forget the soundbar in Bluetooth settings and reconnect whenever I wanna play music, but I don't want to do that. It was quite a pain getting my phone to connect to this particular device (not the phone's fault, my device is finicky), and I'm worried if I remove it from settings I might not be able to get it back.

I just don't understand why turning off Bluetooth wouldn't solve the problem. This can't be intentional, right? What is the point of asking me if I want to use Bluetooth for my call if the Bluetooth is off?