Can I get my new show to be connected to my echo dot and Bose bluetooth speaker at the same time?
All your Echos are interconnected via the Alexa service / internet and configured on your Alexa app.
Do you mean you want to pair your Echo 5 to more than 1 Bluetooth device at the same time for audio output? This you cannot do.
Only one Bluetooth device will be connected for audio output at any one time.