There is a new accessory available on Amazon that's made specifically for the Echo Flex and turns it into a clock.
Called the Smart Clock attachment, it plugs into the USB port on the bottom of the smart speaker, giving it a display so you can view the time or how much time is left on a timer. It also features a built-in sensor that allows it to automatically adjust the brightness during the day.
Designed to work flawlessly with the Amazon Echo Flex, it is sold on Amazon under the brand Third Reality, which also makes motion detectors, nightlights, and other smart accessories that work with Amazon's Echo devices. Just plug it in, and it'll show the time based on your time zone, or it'll display any timers you set through standard Alexa commands. It's a fairly straightforward device.
The only possible issue is the Echo Flex supports a single accessory at once, so if you’ve already paired it with Third Reality's nightlight or motion sensor, you won’t be able to use the clock. Keep in mind there's also the $59.99 Amazon Echo Dot with Clock you could buy as an alternative. It's literally just a regular Echo Dot, but with a built-in clock for showing the time and timers.
The Echo Flex is perhaps Amazon's smallest Echo. It plugs into the wall, has built-in Alexa, and features a small speaker and mic.