The significance of these advances can be highlighted in four aspects. First, SD-TDR demonstrates a universally applicable, low-energy and surfactant-free pathway for synthesizing HEAs with atomic-level homogeneity, addressing long-standing synthesis challenges. Second, the autocatalytic mechanism and elemental-specific role (Pt, Ir, Ru vs. Pd) provide a new theoretical framework for understanding phase formation and multi-element synergy. Third, the precise control over crystal structure (fcc/hcp) introduces a powerful lever for optimizing catalytic pathways by exposing diverse crystal surfaces and active sites, atomically deciphering the "cocktail effect" in HEAs. Crucially, these structural innovations translate into exceptional catalytic performance. PtNiCoCuRuIr nano-frameworks exhibit methanol oxidation activities nearly 15 times higher than commercial Pt black, underscoring the practical promise of this approach. By integrating mechanistic clarity with synthetic precision, it redefines the design space of HEAs and opens the way toward extending these strategies to non-noble systems, paving the path for the discovery of multifunctional catalysts across future energy technologies.