Azure AD Domain name change

Hi,

I am new to the forum, I am wondering if this is the best place to reach out.

I have Azure running in my store across a number of machines connected to it, this is ideal for policy and the ability for users to login across a number of different rooms etc. 

However, we are a fairly new business, I am still learning a number of aspects of Azure/AD. 

Long story short is : I have since changed the business name, ultimately a new domain name etc since opening and since Azure was setup, however I have users including myself that when we login I still have the old 'domain', example 'email address removed for privacy reasons...' but I now would like to amend all of this to be 'email address removed for privacy reasons'. I have seen info online and I can change policy etc to show new domain on desktop- as well as where to amend it. 

My only concern is a lot of these users have personalised desktops, and a few of them have the @olddomain email address.

If I change to the newdomainco.uk is it just a matter of re-syncing and them being able to get on with it. All they have to do is simply enter 'jenjones' and password at the win10/11 lock screens and fine, I am worried they may lose access to things. 

Only myself utilises the onedrive feature, they have scripts that connect to actual network drives. Would it interfere too much?

Any help is appreciated, and apologies if I have posted this in the wrong place. Thanks,

David