Did your total devops cost go up or down? I'm sure aws is less expensive than heroku but I assume now you are paying more to people to do what heroku did?
We are spending about 60% less. Workload has actually lessened since AWS is so much more stable. Getting to a similar DX as Heroku was quite the lift, but once it's done, it's done. These days we generally only have outages when we screw something up ourselves. I recommend https://github.com/aws/copilot-cli for starting out on ECS.
For all heroku's done wrong it has been rock solid for us for nearly 10 years. The only outage I can remember in all that time is when they were having issues with their upstream dns a little while ago. Even this incident isn't causing any down time for us - we just can't deploy updates until it is fixed. I guess if we had a critical fix on deck it could be considered an "outage" though.
Hate to break it to you but you've always been on AWS ;)