I created a journey builder custom REST activity as described here. https://developer.salesforce.com/docs/atlas.en-us.noversion.mc-app-development.meta/mc-app-development/example-rest-activity.htm
The execute arguments give you the chance to at least add retry and timeout. But what about 404 or 500 errors? Currently the activity just continues in the flow.
In addition is the REST activity also logging into any view or dataextension? I would expect or need sth. like SendLogs for Email.