We have a requirement like triggering a custom workflow programmatically on scheduled basis at the same time the scheduler should not trigger a new workflow instance until the existing instance is complete or terminated. Do we have any config or property to manage this or we need to maintain some configs on our own.
You cannot restrict to one workflow in Touch UI you need to use classic UI, if you still want to use Touch UI you need to write a custom script. The restriction we see in the Classic UI is at the UI level. So Classic has it and Touch UI does not. As far as the AEM Workflow engine is concerned - it can have the same page as payloads in multiple workflows. Hope this clears it up.
Please have a look at below threads for more clarification and several alternative approaches we can take: