See in most of the government R&D sectors, there are need of Computer Engineers. But the point is, most notifications are for BTech Students at least for ISRO. There are some technician posts for Diploma students but those are mainly for Electrical Engineering or Mechanical Engineering Diploma holders. SO if you wish to go for it then I would recommend you to obviously go for BTech via lateral entry i.e., you will be able to get admission directly in the 2nd year of BTech. You can apply both in Government/Private colleges. There are two ways of selection one is through entrance and the another is through Merit based. So depending on your state you have to apply.

If you wish to go for private sector, then you can obviously go for it. But in case of the above mentioned field you have asked for, its hard to get a position on the basis of Polytechnic. Because the most vacancies are for BTech/MTech/BE/ME students.

To know more about the Lateral entry examination visit the link below:

https://engineering.careers360.com/articles/what-btech-lateral-entry-eligibility

I hope this answer helps. All the very best for your future endeavors!