Thermoelectric (TE) devices enable robust solid-state conversion of waste heat to electricity, but their wide-spread adoption is still limited by relatively modest efficiency. A widely used approach to improve efficiency is to enhance the power factor through confinement of carriers or energy filtering by potential barriers. However, their relative influence and the resulting improvement in the power factor in two-dimensional (2D) materials is not well understood. Here we study single-layer 2D ${\mathrm{Mo}\mathrm{S}}_{2}$ with lateral potential barriers to introduce either energy filtering or carrier confinement by changing the direction of the electric field, with confinement resulting when the electric field is parallel and energy filtering when the electric field is perpendicular to the potential barriers. We implement a Wigner-Rode model with electronic structure calculated from first principles to simulate the effect of the shape and size of potential barriers on parallel and perpendicular transport. Our results show that the power factor can be doubled, from $25\phantom{\rule{0.1em}{0ex}}{\mathrm{mWm}}^{\ensuremath{-}1}\phantom{\rule{0.1em}{0ex}}{\mathrm{K}}^{\ensuremath{-}2}$ without barriers to over $50\phantom{\rule{0.1em}{0ex}}{\mathrm{mWm}}^{\ensuremath{-}1}\phantom{\rule{0.1em}{0ex}}{\mathrm{K}}^{\ensuremath{-}2}$ for parallel transport in sharp, narrow potential wells. Perpendicular transport in smooth barriers results in a higher power factor compared to sharp barriers, while sharp barriers perform better in the case of transport parallel to the barriers, especially at small barrier widths. Our results aid in improving TE power factors and further the development of efficient waste-heat scavenging, flexible 2D TE converters, and Peltier cooling of nanoelectronics.