How often is that really required? OP asked for a quick deploy, for most apps it's enough to put the db into read-only mode and then update the schema. Upgrading the app binary is as simple as replacing it on the file system and then restarting the service.

The more often we deploy with CI/CD, the more we need zero downtime deploy. Putting the DB in read-only mode is not that simple, because the app needs to be able to work in a degraded read-only mode.

Yeah DB migrations are a pain in the bum. I do them manually because I still haven't found a tool that handles them properly.

But by the time there's significant data to migrate to the new schema, any schema change is usually due to a major version change or feature implementation, and the migration is part of a wider pain-in-the-bum situation.