I found this solution on Reddit and can confirm it works, so now you can add a routine to Alexa so that saying “Alexa, unlock” (or similar) will cause the Ring Intercom to unlock your door without you having to say your voice code.
Security concern? Yes, maybe, but I guess that’s for you to decide - for me, it’s the front door to my building not my property, and there’s far easier ways to open the door than hacking an Alexa!