microservice communication, sync or async? that's the big question

hey folks, working on a new microservice architecture and I'm trying to nail down the communication patterns. We're leaning towards async using message queues for most things to avoid tight coupling and improve resilience. But for certain workflows, like a user placing an order and needing immediate confirmation, synchronous communication via direct calls or an API Gateway seems necessary. What are your go-to strategies for deciding when to use synchronous vs. asynchronous communication between microservices? Any patterns or heuristics you find particularly effective?