We investigate the ground-state properties and topological transitions of spin-1 SU(3) spin-orbitcoupled Bose-Einstein condensates (BECs) confined in a radially periodic potential, with a focus on the regulatory mechanisms of long-range soft-core interactions on the system’s spin textures and topological structures. The theoretical results are obtained by self-consistently minimizing the Gross-Pitaevskii energy functional, which incorporates the competition among the external trapping potential, spin-orbit coupling (SOC), spin-dependent contact interactions, and the nonlocal soft-core repulsive potential. For the system with a central potential barrier, in the absence of soft-core interactions, the interplay between SOC and spin-dependent interactions leads to a ring-shaped periodic density-peak structure accompanied by the spontaneous generation of a vortex lattice. However, when the long-range soft-core interaction is introduced, the strong nonlocal repulsion triggers a distinct spatial phase separation, where a circular domain wall emerges to sharply separate a central spin-uniform macroscopic domain from the surrounding spin-density wave background. Conversely, for the system with a central potential well, the system initially presents a low-density core region. A transition from the antiferromagnetic to the ferromagnetic spindependent interaction causes the ground state to transform from a continuous bright ring into a discrete array of localized wave packets. Upon introducing a soft-core repulsion characterized by a suffciently large blockade radius, the system is driven into a highly ordered vortex lattice state. Furthermore, our analysis reveals that when the long-range soft-core interaction dominates over the SU(3) SOC effects, the nonlocal repulsive force effectively suppresses the spatial modulations induced by SOC, leading to a uniformly smoothed density profile and a globally aligned spin texture. Crucially, our findings demonstrate that the various ground-state phases arise from the synergistic competition among four physical effects: spindependent interactions, SOC, long-range soft-core interactions, and the trapping geometry. By tuning the soft-core strength, the blockade radius, and the potential configuration, distinct vortex lattices can be selectively excited. This work not only reveals the multiple physical origins of topological structures in SU(3) spin-orbit-coupled systems but also provides a theoretical scheme for the controllable preparation of diverse topological states in multi-component quantum gases.