I believe, the singleton VM spun up by release_command is ran in the primary_region: App Configuration (fly.toml) · Fly Docs
Also, there’s a lot more control to be had over deploys if you use Machines. Though, giving up even more control and offloading database to a managed provider (like PlanetScale or EdgeDB, say) is perhaps the easiest of options (vendor lock-in not withstanding)?