So uh, as someone stuck on Android 8 forever, what am I supposed to do? Just get a new phone?
If you need Bluetooth then check whether your phone has the same Broadcom driver - you might be fine depending on hardware. Or check if you can install open source firmware that includes a fixed driver.
There are other things you can do depending on device.
But it's less of a problem in iOS anyway, because Apple provides updates for iPhones much longer. They are still releasing security updates for the iPhone 5s and 6, which are from 2013 and 2014 respectively.