  We present a re-analysis of the shear and galaxy clustering data from
first-year Dark Energy Survey data (DES Y1), making use of a Hybrid Effective
Field Theory (HEFT) approach to model the galaxy-matter relation on weakly
non-linear scales, initially proposed in Modi et al. (2020). This allows us to
explore the enhancement in cosmological constraints enabled by extending the
galaxy clustering scale range typically used in projected large-scale structure
analysis. Our analysis is based on a recomputed harmonic-space data vector and
covariance matrix, carefully accounting for all sources of mode-coupling,
non-Gaussianity and shot noise, which allows us to provide robust
goodness-of-fit measures. We use the AbacusSummit suite of simulations to build
an emulator for the HEFT model predictions. We find that this model can explain
the galaxy clustering and shear data up to wavenumbers $k_{\rm max}\sim 0.6\,
{\rm Mpc}^{-1}$. We constrain $(S_8,\Omega_m) = (0.782\pm
0.018,0.279^{+0.023}_{-0.033})$ at the fiducial $k_{\rm max}\sim 0.3\, {\rm
Mpc}^{-1}$, improving to $(S_8,\Omega_m) = (0.784\pm
0.016,0.270^{+0.019}_{-0.029})$ at $k_{\rm max}\sim 0.5\, {\rm Mpc}^{-1}$. This
represents a $\sim10\%$ and $\sim30\%$ improvement on the constraints derived
respectively on both parameters using a linear bias relation on a reduced scale
range ($k_{\rm max}\lesssim0.15\,{\rm Mpc}^{-1}$), in spite of the 15
additional parameters involved in the HEFT model. Our constraints are
investigative and subject to certain caveats discussed in the text.
