Hey,

Aspirants who intend to pursue undergraduate courses in the United States and other nations take the SAT 2021 exam. The internationally recognized SAT exam 2021 is administered by the College Board and tests a candidate's academic competence in Reading, Writing, Quantitative Aptitude, and other prescribed specialized topics.

So, basically, SAT exam is for admission into the undergraduate programs. As you have already pursued your B.TECH, you would not want to repeat your undergraduate degree as such. So, generally, there is no as such use of SAT after passing B.TECH degree, unless or until you want to again pursue your UG degree from US and other countries.

Know more about it here: https://studyabroad.careers360.com/articles/sat