Certain models you are able to flash to get them local, but the issue is that the Vesync app requires your DNS to always be set to 8.8.8.8 and nothing else.
I have the 200s that I bought to replace my dumb one I was using at the time but the main reply I got on the thread mentions that the 300 and 400 are the ones that can be made to be local, I have yet to try with my 200s as I am looking at a matter based one for when its time to replace it and I don’t think it has what I would need to flash it: