  We present a comprehensive study of the angular structure functions for
Drell-Yan leptons in $Z/\gamma$-boson production within the framework of the
transverse momentum dependent (TMD) factorization theorem, including kinematic
power corrections (KPCs). We find good agreement with the data in the
applicability region of the TMD factorization theorem. The inclusion of KPCs
allows us to describe all angular coefficients in a frame-independent manner
using only the leading-twist TMD distributions: the unpolarized and the
Boer-Mulders functions. The value of the Boer-Mulders function is determined
using the ATLAS measurement of the $A_2$ angular coefficient. The analysis is
performed at N$^4$LL perturbative order. Additionally, we discuss the technical
implementation and impact of KPCs on the phenomenology of TMD distributions.
