Ok I apologize for not following directions specifically, but as I mentioned, I wanted to try and see if the original dimmer was actually bad, or if the failure (mechanically) of the slave switch caused the issue somehow. I admit to not being very saavy with Hubitat so again, I apologize.
That being said, what happened when I excluded the original kitchen dimmer, was I put the Hubitat into exclusion mode, then hit the on side of the switch, and Hubitat showed "unknown device excluded" or something to that effect. At that point, I tried to put the dimmer switch into factory reset mode (tap on 3 times, then tap off 3 times and LED should blink 5 times), however, I was unable to get the dimmer into factory reset mode, IE I never saw the 5 blinks.
From there, I performed the Z-Wave include or add step, and added this dimmer back into the mix, whereby Hubitat reported the proper name and type of switch etc. (Not "unknown Z-Wave device"). At that point, as mentioned, I did the swap device step from the virtual switch to this one and it all worked.
I never actually tried a "remove device" action because I didn't want to cause any issues, since the excluded and readded switch was now working like it always has.
SO.... At this point, I just followed your remove device steps above and BOTH the virtual and original instances are gone from the devices menu! I also renamed the new Kitchen dimmer switch (instance) successfully, so I think I am good?
I am one of those people who once I have spent the time to get something up and running the way I like it, I tend to walk away, and then the familiarity with how I actually got there seems to get purged from my brain, which is exactly the case here. I bought these switches and my Hubitat in 2019, spent a week getting it sorted out, and aside from the occasional hard reboot, have never once had to "fix" anything, so it has been 4 years that I have not had to think about it really, which is saying something for how well these (Hubitat) systems are designed. I am a fantastic example of: "Hubitat seems to be idiot proof".