I'm confused. Has the Alexa app changed? If I go to Routines I'm shown existing routines, featured routines, and I'm offered an opportunity to create a new routine (the "+" at the upper right corner). The "devices" button is at the lower right corner, and touching that will take you out of "routines." So I've got two choices (neither of which matches what you've said here) - Go to devices and try to set up the Ring camera there (as we know, that doesn't work), or to create a new routine. Creating a new routine there is no "motion" variable "when this happens." Going to "Smart Home" offers an opportunity to use the Ring camera, but the only variable available is "not detected" or "detected" - not a schedule. Sure could use some help here. Perhaps this is something that cannot be done. Sure would be nice to have the Ring app integrate fully with Alexa, as do the apps for Nest thermostats and Kasa lighting.
What finally broke our will in turning it off on Alexa is the well-known propensity for a Ring to greet the dawn with an alert. . . in the master bedroom at 5am. Doesn't take much of that to convince one this was not such a great idea after all.