One other thing to note is that you should not put any long running processes in %ZSTART as they will hold up the Start process.
If you have to, then consider JOBbing it off to a separate process, so it can run in the background and allow the rest of the startup steps to run in parallel.
You can customise the refresh at the Backup Stage, you can define the list of Databases that will be Backed up before running the Backup.
See here for more details:
https://docs.intersystems.com/iris20241/csp/docbook/DocBook.UI.Page.cls?...
But please make sure you test this in a development environment before touching your live system.
Deferred only relates to the unlock command, see here for some more details.
Basically, the unlock does not happen immediately, it will be done at the end of the transaction. ideally, this is what you want, and as long as your transactions are quite quick, it won't be an issue.
https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cls...