The high-energy tails of charged- and neutral-current Drell-Yan processes provide important constraints on the light quark and antiquark PDFs in the large-x region. At the same time, short-distance new physics effects such as those encoded by the Standard Model Effective Field Theory (SMEFT) would induce smooth distortions to the same high-energy Drell-Yan tails. In my talk, I will discuss the amount of interplay between PDFs and new physics effects for high-mass Drell-Yan processes at the LHC and quantify the impact that the consistent joint determination of PDFs and Wilson coefficients has on the bounds derived for the latter. The main finding is that, while the interplay between PDFs and EFT effects remains moderate for the current dataset, it will become a significant challenge for EFT analyses at the HL-LHC. I will also discuss ongoing studies aimed at disentangling the effects of new physics in PDF fits.