i see!
in my view you can see depersonalisation as "switching out", which would be part of the process in the 1st case described by ranger
it is actually something that some people in tulpamancy would like to achieve, having tulpa front and the host just being "switched out"
i personally don't think that's a good idea to train towards but since you already depersonalise, i might share some of my thoughts
you might notice that your tulpa might have different triggers than you do, meaning that for them it might be easier to not be depersonalised.
you might notice that your switching is disrupted by depersonalisation - however i wouldn't pay attention to that too much. i am often depersonalised when i front, but it is still me acting. there is no reason to take that away from yourself.
at some point you might notice that there is a dynamic between depersonalisation and switching, so you will see that working on depersonalisation will help you with switching, but also learning to switch can play a part in managing depersonalisation. the only thing you need to remember is to not worry and not work yourself too hard, because that can cause you anxiety that will as you probably expect build more depersonalisation