CA ROOT certificate template - expiring

Question

Hello,

I would like to know is there any possibility to create a new template of CA ROOT to make some tests on new enviroment. For next few months our CA Root Certificate which is connected strictly into domain will be expire. I just wondering is it any chance that we can create some kinds of template this type of certificate and test it on fx. vm which is not connected tio the domain to check how is it working? I found some articles that shows how we can extend exsisting certificate, but none of them can show how we can create template of them. Maybe when its nos possible to create a template of CA ROOT, we can create another type of CA which can be good for testing.

Thanks for any advice.