A recent Letter by Zhu et al [Phys. Rev. Lett. 127, 247702 (2021)] claimed a unified mechanism for quantum oscillations (QOs) in graphite-gated 2D devices based on studies of three cases (WTe2, MoTe$_2$/WSe$_2$ heterobilayers and bilayer graphene (BLG)). We find that not only are the claims of Zhu et al based on insufficient evidence in all three cases but also critical aspects are ignored. Their conclusions are hence unreliable.