For your salary your credit limit seems too low ,
I'm a senior resident in a medical college, earning similar to you, but my highest card is ICICI with limit of 6L ,but then again I've been in this game for close to a dacade ,got my 1st card when i was in 2nd yr MBBS,
I would suggest first try to get credit limit enhancement for all your cards based on your ITR ,get ICICI cards as they give good credit limits ,
Also get Regalia Gold right away, should be easy with 12L ITR ,and then you try to upgrade later on ,
DCB is a bit tricky in your position ,you'll have to convince your bank employees to take deviation on salary requirements, totally depends on them