S it good to do DNB courses than MD or I can give another attempt again fa Neet 2020

the answer to this question completely depends on how was your exam went or what DNB course your getting in which college and whether you have a fascination for government jobs or are ready to be adapted into a private sector occupation after you complete your medical master degree
pursuing a DNB degree in internal medicine in a reputed Hospital like Apollo are those associated with the railway services of the different metropolitan States is often a much better degree then and Ms or MD pursued in a remote college of some smaller state
on the other hand if you are trying to add for government jobs and Ms or MBA degree will always be more handy you since it will help with your clinical learning more with regular seminars and lectures being held which will not be available with your DNB which is usually popular in medical circles to be known to be difficult to crack in one attempt.
overall if you are getting admission into an MBA or Ms course then go for it, if you are not please look at which DNB course and in which college you are getting and whether you are happy with it then you cannot forget else you can try for your Neet examination next time but keep in mind that if you have an opportunity this time not availing it and waiting for the next year can disappoint you if your exam doesn't go as well as it went this time, the next time around