Starting out on Digital Ocean or Heroku is usually a great idea.
I consult with companies that are looking to move in the other direction, from Digital Ocean to AWS.
Their biggest pain points as they grew are:
1. The lack of granular permissions scoping and access control.
2. The networking primitives in Digital Ocean ended up being too restrictive. For example, they wanted to have static egress IPs and it was much harder to do that in Digital Ocean than AWS.
3. The need for more of the managed services AWS offers.
Did you compare between DO, Lightsail, Vultr, Linode, etc. or was the difference between that tier of offering so little that you just picked one and ran with it?
At this phase of the startup, we aren’t missing a beat.