Fitting new architecture design in Scrum
My team is working on creating a new framework / rendering engine, from scratch - essentially rewriting and reimagining. The vision and the plan came from an architect to the team's backlog. It then ties into rewriting 2 areas of our product into this new framework. At the moment, its going through weeks of spike work, followed by another phase of setting up new repositories, etc. by our Scrum team. As a Scrum Master, it doesn't feel like this is the most agile way of working on this - as in "delivering working software every sprint." I'm struggling a bit on where this fits into the Scrum framework, and the product backlog especially. Should it not start from the Product Vision, down to epics and stories around the value of rewriting areas of the product, and the architecture pieces as the "how" / tasks under those epics and stories? Any guidance is most welcome.
When you consider all of that rewriting and re-imagining, and work being done from scratch, how will the various assumptions and hypotheses be tested? How will an emergent architecture be validated? What approach to validated learning is being taken here?
Isn't it worth delivering something every Sprint which enables the inspection and adaptation of the evolving product, no matter how small that something may be?