I tried on my Poco (Xiaomi).
I had Dual Clock on but never switched the second one from the same place.
If you set a second clock as it says for a location in a different time zone - they both appear as two digital clocks on my lock screen, or two analogue clocks on my AOD (the style I had set.)
I set it for London and New York to demonstrate. It seems to be for the lock screen and AOD only.
Edit : I don't see a widget for dual clocks, though I don't have my other Mi 10 Lite with me.