yes but show mode solves the always on power requirement via the special dock.
you can them probably disable alexa without losing show mode
on a fire tablet ( outside of show mode) alexa is disabled if you turn on parental controls
now all you need as a calendar or time app with preferences that you can tweak, and have it always running, I expect the app store has lots of candidates. dont rule out weather apps as they also display time
alternatively, a cheap micro PC ( which can be hidden away) connected to a wall mounted screen would seem to be a better way forward. Something like an Lenovo M93p tiny which you can pickup on ebay. Or an Acer veriton. avoid cheap no-name crap in amazon marketplace ( like ACEPC) and get a reliable brand - but old & used will be fine
the 2 I named are about the size of a hardback book, can be wall hung or stashed away horizontally or vertically. Have a usb KB/trackpad combo that you can unplug once the PC is up and running, and reconnect if you need to tweak stuff
https://www.amazon.co.uk/Lenovo-Thin.../dp/B00E2TYAXS
https://www.amazon.co.uk/Acer-Verito...mputers&sr=1-5