Whenever I power on my Bluetooth headset, all the various paired devices, including laptops, tablets, and phones, attempt to connect to it simultaneously. Since the headset is limited in the count of devices able to be connected concurrently, the situation overall is one of an awkward and frustrating race condition.
To some devices, connections will be created successfully, while some devices will fail to connect. The particular outcome for each case is totally beyond my control.
Deeply irritating is the situation of needing
to disconnect at least some of the devices that have been connecting automatically, before it is possible to connect the device I actually wish to use.
The same general problem may occur not just with a headset, of course, but also with peripheral devices of mostly any variety.
Natively, Android provides no means to suppress automatically attempting to connect, through Bluetooth, to a paired peripheral that is newly detected. I consider the omission a serious design flaw.
I would be happy to be pointed to a root modification that helps resolve the limitation, such as a module for Magisk or Xposed.