.ac or .bode export data into (real,imag) rectangle complex number format. Currently, Qspice doesn’t have option to export as polar (magnitude, phase), and you have to post-processing by your own.
discussion post in this topic (with matlab code example for conversion)
https://forum.qorvo.com/t/is-there-a-problem-with-export-data/17723/7
https://forum.qorvo.com/t/single-frequency-analysis/22353/5