Architecture exists to guide teams towards strategic solutions and help make sound trade offs between strategic and tactical solutions when required.
The skills and expertise required to perform architectural tasks (managing technical debt, negotiating trade offs, ensuring operability and scalability of solutions) sit primarily within DevOps teams, not in discrete architecture roles.
Architectural roadmaps and roles, if they exist at all, should be aligned to Customer Journeys and focus on defining the vision for that journey and how it will be realized (working closely with the customer journey owner). Note that this is not just about technology – the vision will be described from the perspective of the customer.
If proven to be of value, Roadmaps will be produced collaboratively with the relevant technical teams, there is no separate team of “Enterprise Architects” to do this.
Consistency and “Rule of One” have no inherent virtue, but may have value – if Rule of One is applied as a constraint on teams, the value of doing so must be agreed with them and set against the loss of autonomy that inevitably results.