How do you save money from multicloud when you have to start paying DTO. E.g says your compute's on EC2 and you use GCS, now your paying DTO for something that was free.
That’s not true at all. AWS start charging you as soon as the data leaves an AZ. In fact, if you use a direct connect you only need to pay 2c/GB to egress out of the region (which they most certainly pay are) which is what you'd pay anyway to another AWS region. Realistically, the data transfer costs are negligible (compared to multi-regional/inter-zonal costs) when the network has been engineered correctly. You’re always going to pay but you can limit to what extent.