Hi,
Currently the scheduler tile is the only way to control customer journey process.
Even though with custom channel tile and a flow which contains a Delay action, it will just wait 5 minutes after creation of custom channel activities and then do further actions,
but delay of the customer journey itself won't be affected. In other words, these are two independent processes.(flow on creation of custom channel activities vs customer journey)
From 2020 wave 2 release plan, there will be two new tiles: "Wait for" and "Wait until" to control journey,
however, the date of early access is September, and from the published content, I'm not sure whether "wait for 5 minutes to send marketing email" feature would be also available in the future.
Welcome to send any feedbacks of yours to Ideas forum.
Regards,
Clofly
