A comprehensive first-principles study on electronic structure of optimally doped Ca0.33Na0.67Fe2As2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\hbox {Ca}_{0.33}\\hbox {Na}_{0.67}\\hbox {Fe}_2\\hbox {As}_2}$$\\end{document} under hydrostatic pressures in the presence of magnetic configurations is presented. A magneto-structural transition from a tetragonal to a collapsed tetragonal phase at 3 GPa hydrostatic pressure is predicted in double-stripe antiferromagnetic configuration that corroborates experimental observations. As the system enters the non-superconducting collapsed phase, significant deviations occur in the local structural parameters compared to those at optimal Tc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\it{T}}_{c}$$\\end{document} values. This transition coincides with a sharp decrease in As density of states (DOS), accompanied by Fe magnetic moment collapse and substantial Fe square plane charge density modification. The structural transition induces a comprehensive reconstruction of the electronic structure, marked by distorted FeAs4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {FeAs}_{4}$$\\end{document} tetrahedra, potentially leading to unfavourable nesting conditions, and complete suppression of magnetism, correlating with the observed disappearance of superconductivity. Increasing pressure leads to a rise in crystal field splitting, influencing the spin-state transition in Ca0.33Na0.67Fe2As2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\hbox {Ca}_{0.33}\\hbox {Na}_{0.67}\\hbox {Fe}_2\\hbox {As}_2}$$\\end{document}, ultimately resulting in a shift from tetragonal to non-magnetic collapsed tetragonal phase as the Fe2+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {Fe}^{2+}$$\\end{document} spin state transitions to a low spin state. This demonstrates the intricate interplay between crystal field splitting, external pressure, and spin dynamics, highlighting the significant impact of magneto-volume effects on the structural phase of material under pressure.