How are teams planning AEP + App Builder adoption alongside existing Adobe Commerce implementations?

We are seeing more clients asking about progressive modernization instead of full replatforming.
In several Adobe Commerce projects, the discussion is no longer only about storefront replacement, but also about how Adobe Experience Platform (AEP), App Builder, and event-driven architecture can coexist with existing PaaS implementations.

Some common questions we are evaluating internally:

• How are teams introducing AEP capabilities without disrupting current Commerce operations?
• Are you using App Builder primarily for integrations, custom APIs, or operational workflows?
• What are the biggest architectural challenges during phased modernization?
• How are you handling legacy custom modules during transition planning?
• Are clients already preparing for ACCS readiness through composable services?

Would love to hear how other teams are approaching:

• phased migration strategy
• event-driven integrations
• operational governance
• data synchronization patterns
• AEP adoption challenges

Interested in learning from both implementation and architecture perspectives