Desktop Clock
If you right click the clock, then cursor over Settings, suggest you click - On top, Load at Startup, Chimes, the clock will then display on top of each screen, suggest drag it to bottom right of screen.
The link does not specify Windows 10, but I have been on Windows 10 for two years with no clock problem.
http://www.respectsoft.com/vistaclock.php
The download button is the orange bar 6 inches down the link page.