I don't know how Ultrathink works, and I have no "real world" experience with Kamal, but I find it intriguing to see someone consider 11 deployments in 2 hours to be "fast".
Instead of handicapping yourself, fix your deployment pipeline, 10 min deploys are not OK for an online store.
I would have liked to read about the "high availability" that's mentioned a couple of times in the article; the WAL Configuration section is not enough, and replication is expensive'ish.
There's also a `Surprisingly written by a human :)` at the bottom.