You mention you have switched to using Runtime Environments, please note this item in the docs:
Currently only cloud jobs are supported for newly created runbooks linked to user-created Runtime environments. However, you can link the newly created runbook to system generated Automation Runtime Environment to execute it as a hybrid job.
So if this job is attached to a user created run time environment, then you cannot currently use a hybrid worker, You would need to use one the system generated environments.