Abstract Recent observations from the Atacama Cosmology Telescope (ACT), especially when combined with DESI baryon acoustic oscillation data, indicate a scalar spectral index nₛ n s higher than the value reported by Planck 2018, placing tension on universal inflationary attractor models. Motivated by this discrepancy, we investigate the inflationary predictions of the β -exponential potential, V () =V₀ (1- /Mₚ) ^1/ V (ϕ) = V 0 1 - λ β ϕ / M p 1 / β considering both minimally and non-minimally coupled realizations. This potential generalizes standard exponential inflation and naturally arises in braneworld scenarios. We derive analytical expressions for the slow-roll parameters and inflationary observables using a perturbative expansion in the non-minimal coupling ξ, and validate these results through numerical calculations. In the minimally coupled case, the model predicts nₛ 0. 976 n s ≃ 0. 976 and r 0. 035 r ≃ 0. 035 for N=50 N = 50 and moderate values of β, remaining compatible with ACT+DESI (P-ACT-LB) constraints at the 1 1 σ level while yielding a spectral tilt larger than the universal attractor prediction. Introducing a small non-minimal coupling significantly improves agreement with observations by suppressing the tensor-to-scalar ratio while preserving the enhanced scalar tilt. For N=60 N = 60, 0. 3\!-\!0. 5 λ ∼ 0. 3 - 0. 5, and O (1\!-\!5) β ∼ O (1 - 5), the non-minimally coupled model yields nₛ \
Yuennan et al. (2026) studied this question.