Abstract

We study quark star configurations in regularized four-dimensional Einstein-Gauss-Bonnet (4DEGB) gravity using a QCD-motivated equation of state with parameters B<inf>eff</inf>, a<inf>2</inf>, and a<inf>4</inf>. The modified Tolman-Oppenheimer-Volkoff equations, incorporating 4DEGB corrections, are solved to examine mass-radius relations, tidal deformability, and stability across a range of α, a<inf>2</inf>, and a<inf>4</inf>. Positive α or larger a<inf>2</inf> yields more massive, compact stars than in general relativity, with some configurations below the GR Buchdahl limit, potentially eliminating the mass gap with black holes. The dimensionless tidal deformability Λ decreases markedly with α and a<inf>2</inf>, while a<inf>4</inf> has only a minor effect. Models consistent with NICER, GW170817, and HESS J1731−347 constraints remain dynamically stable and causal. Our results demonstrate that the interplay between higher-curvature gravity and QCD microphysics can produce observationally viable deviations from general relativity, offering promising targets for future multimessenger constraints on dense matter and alternative gravity theories.