This is the first time JIPMER will be giving admission on the basis of Neet Score. So we don't have any idea about the previous year's cutoffs, we don't have any reference. But there are total 249 seats (JIPMER Puducherry (187) and Karaikal campus (62) and 55 seats foe ur category in Piducherry and 19 in Karaikal) offered for MBBS in JIPMER. So it can be expected that an all India rank within 300 to 350 can fetch you a seat in JIPMER Puducherry. Now as you told, you have scored 676 in Neet 2020 out of 720 and your rank is 834. With this rank it would be difficult to get JIPMER Puducherry campus but you can try for Karaikal.

AIIMS Bhubaneswar might be difficult but you can expect AIIMS Patna, Bhopal, Raipur.

Or else, government medical colleges of Delhi such as VMMC are achievable with this rank. Also you can use our Neet college Predictor tool to know about your admission possibilities through Neet based on your score and rank http://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer