Comprehensive timing analysis and evolution of the periodic signals in V1674 Her. Top: Lomb-Scargle power spectrum in the orbital frequency range (6.0–7.0 d⁻¹) for Sectors 40 (cyan), 53 (magenta), 54 (black), and 80 (red). The dashed line represents the 99% significance threshold for Sector 80, calculated using an AR(p) red noise model to account for stochastic flickering. Middle: Individual phase-folded orbi tal profiles for each sector, taking T₀ = 59873.817 from Dubovský et al. (2024) and binned into 30 phase intervals with 1σ error bars. Bottom: Lomb-Scargle power spectrum in the spin frequency range (171.5–173.5 d⁻¹) from Sector 80. The inset shows the binned spin pulse profile with associated 1σ uncertainties. All reported periods and uncertainties were derived using 200-iteration AR-integrated Monte Carlo simulations to ensure robustness against the colored noise background of the post-nova state.