Your general category rank is not affected by your caste certificate. You will also get EWS rank but of you are not able to produce the certificate , then the seat alloyed to you on the basis of EWS rank will not be considered and they will shift yoylu to General Category.

EWS rank would help you a little bit it is your talent that would drive you to a worth College.

You should also try to get the certificate. It may help you in future. But remember that it should be issued after April 2020.