Any way to improve this call site? (is intended to be lazy loaded for logging - based on severity some might not get evaluated at all)

log.error(e, { "Error logging in user" }, { mapOf("email" to email) })

In Swift you have the option to use

@autoclosure: () -> String

and then the call site is

someFunc("mylog")

Is there anything like that for Kotlin?

Not that I know of.