Bluetooth & Linux, pain in the butt

Thanks for all the answers, I didn't have time to post here but did some bluetoothing around. I maintain that BT under linux is a pain and it shouldn't. However, here is what I found out so far:

1. My initial observation was from ubuntu studio 21.10. After @Fteacher mentioned LinuxMint I remembered that I still had a Mint partition. So I booted into it and it worked with internal BT once. Then it didn't. Put it in the dongle and got it to work. Now, after a week, it works on the internal. I don't know what's going on. But it works.

2. rfkill shuts down all BT. At least on a superficial level. Somehow with bluetoothctl one power one off, still connect with the other one but the GUIIs will not see any BT.

This is all confusing but at least right now it is working for me.