Manage different report versions across multiple tenants.

Hi
I am a freelancer data professional and I was wondering to see if my idea is possible.
Today, I develop PBI reports based on data which is coming from ERP systems. I created a sales report which helps my clients get insights from their sales ERP data. Let's call it the “product” / “the standard PBI report”.
 
As I got more and I got more clients, I leverages previous PBIX files from existing clients and used them on new clients.
Today, each time a new client purchases the product, I connect to his ERP DB, create the dataset publish the reports (it is mostly copying and pasting PBIX files and updating parameters in the data sources).
The product is used by the users through PBI Service (not embedded) using a pro license. When a new client purchased the product, I create a new Azure AD tenant and deploy the report and the dataset in this tenant.
I manage all tenants for the clients.
 
For several months, clients started asking to customize the “Start PBI report” in order to get better insights (adding measures, adding visuals with KPIs specific to their business).
Since the architecture allow me to do it, I did it. Over time few clients got real far from the “standard PBI report”
 
Today, if I have a new idea for a new visual (what I called a new “version”) and I want to add to the “standard PBI report” I can do it for new clients only. Because if I want the older client to enjoy the new version, I will need to go to each tenant separately and publish the new PBIX file on their PBI service.
It is time-consuming now, but while the business keeps growing it will be impossible.
 
My question is can I enjoy both worlds?
My vision is to be able to deploy the “standard PBI report” dataset and customized it according to my client's request

BUT when I have a new version of the "standard BI report" I will be able to upgrade it while keeping the customized area?

So it actually to have something which is half SAAS half regular BI development

Can you think of an architecture that allows me to do it?

I did not find anything about it…
I have the developing skills and I can get the support
 
Thank you, Tal