Both the branches are totally different from each other so first decide what you want to study for the next 4 years. Both the IITs are new and there is not much difference in them. Metallurgy is a sub-branch of mechanical and civil is a core branch. Civil engineering has better job opportunities if you compare it to metallurgy engineering.
The average package at IIT Indore for the year 2019 was 16.05 LPA and at IIT Bhubaneswar it was 11.44 LPA. If you want to get a job in the core-sector then it would be a bit difficult because both the branches have very low placements in the core sector. Students usually go for higher studies and others for non core placements. Civil engineering will give you a better opportunity if you want to go for higher studies.
The suggestion will be that you should focus on what branch you are more passionate about and choose that. Don’t go compare colleges, both are IITs therefore are equally good and offer similar facilities.