A set of measurements for the production of a $W$-boson in association with high-transverse-momentum jets is presented using 140 fb$^{-1}$ of proton–proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV collected by the ATLAS detector at the LHC. The measurements are performed in final states in which the $W$-boson decays into an electron or muon plus a neutrino and is produced in association with jets with $p_{\text {T}} {EMPTY}>30$ GeV, where the leading jet has $p_{\text {T}} {EMPTY}>500$ GeV. The angular separation between the lepton and the closest jet with $p_{\text {T}} {EMPTY}>100$ GeV is measured and used to define a collinear phase space, wherein measurements of kinematic properties of the $W$-boson and the associated jet are performed. The collinear phase space is populated by dijet events radiating a $W$-boson and events with a $W$-boson produced in association with several jets and it serves as an excellent data sample to probe higher-order theoretical predictions. Measured differential distributions are compared with predictions from state-of-the-art next-to-leading order multi-leg merged Monte Carlo event generators and a fixed-order calculation of the $W+1$-jet process computed at next-to-next-to-leading order in the strong coupling constant.