I don't know what Google uses. But pretty much you can be tracked in so many ways. Your identity can be associated with your IP. Or the Mac address on the hardware in your computer (kind of like a cars VIN). And you have Gmail accounts associated with those things. If you ever signed into Google account using the same ip or Mac address. Even AdSense does a pretty good job making sure you only create one AdSense account for all of your YouTube accounts.
If you want to create a new identity you probably need to really create new identity. New PC, new address, new Google accounts, new bank account all of these things that do not have prior associations with each other.
I Don't know If YT looks at all this when flagging channels. Maybe not necessary to go so far to create new channel. But lots of things to consider about this tracking stuff. Google could associate your identity through your phone. They would know if you are accessing your new channel from the same GPS location where you used to access your old channel. And then create an association that way. They probably don't go that far. But it can be done.