Architecture is simple
You start your work to identify what you provide to your customers:
Products
One time services
Reoccuring products
Reoccurring services
and then your customers:
Individuals
Organisations
Retail
Agents
With only two boxes from a business model canvas, we now have 4 * 4, i.e. 16 options to manage in our IT-systems. Then add four more customer relationships, four more channels and four revenue stream from a business model canvas. We now have 4 * 4 * 4 * 4 * 4 variants for selling our products, i.e. 1024 variants.
If you then add four different types of partners into the mix, you have 4096 variants to implement as end-to-end-flow in your IT-landscape, and this is just one country.
To resolve this complexity in IT for an existing organisation is a very complex task and requires lots of hard work.