We use camunda community edition packaged in Wildfly. We use rest api for starting workflows. All our workflows are async – so they executed through job executor of camunda.
We are not trying to get the current running workflows – meaning the jobs locked by the executor, i know we can get it through camunda DB using query.

SELECT COUNT(*) FROM ACT_RU_JOB
WHERE (LOCK_OWNER_ IS NOT NULL AND LOCK_EXP_TIME_ >= NOW())

But i searched for REST API of camunda to achieve the same but couldn’t find any. I went through https://docs.camunda.org/rest/camunda-bpm-platform/7.21/#tag/Job/ But no use.