I'm not sure the math is so easy. Even knowing the direct cost savings in hindsight, engineers' time is expensive, and it's not obvious that the ongoing engineering cost of maintaining Trino on an EC2 cluster would be that far below $22k/month. Even if you get a net cost savings on an ongoing basis (which, granted, you probably do), you may have a long payback period for the initial engineering time spent evaluating solutions and getting the deployment spun up.
And that's all with the benefit of hindsight - it's hard to know a priori how much cheaper your own deployment will be compared to a managed service or how long it will take to implement. Of course, anecdotes like yours help with that, so thanks for sharing your experience!
