Should I pursue B.Tech from a UGC approved college or from an AICTE approved?

Approval whether UGC or AICTE etc are only benchmark clearance from statutory bodies. You must select institute for engineering studies based on Institute rankings. You may refer to https://shiksha.com portal engineering link for ranking of engineering colleges.

You should do it from an AICTE approved college.

According to the guidelines an engineering college should be either UGC approved or AICTE approved. Some of the universities are Lovely Professional University, NOU, Dr. B.R. Ambedkar Open University, IGNOU etc.