For JEE Mains, you cannot use a Rajasthan state general EWS certificate and need to obtain a central EWS certificate to claim the EWS category reservation benefits in your application form because JEE Mains exam is conducted at a national level, so the reservation benefits are based on a central EWS certificate issued by the appropriate authority, not a state-specific one even if you are a dropper it has nothing to do with caste certificate.

If your are under ews category at central level Contact your local district administration office to initiate the process of obtaining a central EWS certificate.it can be also issued in states too even everything is online in today's world so go for it.