Δχ² map for PSR J2222–0137 from simulated data (2021–2030) combining different observatories and using the MPA1 EOS. Assumed one orbit per year for FAST, MeerKAT (MK), and 3ERT (EFF, NC, LT) based on their observation precision, appending to the existing dataset (Guo et al. 2021b). Each contour corresponds to 90% CL limits on DEF gravity parameters from different datasets, grey line depicts the limit from the Cassini mission.