A fractional space–time Cahn–Hilliard (FSTCH) model using Jumarie’s modified Riemann-Liouville derivative with order \(\delta _1\) and \(\delta _2\) is examined in this work. This model has extensive applications in various domains, including optics and plasma physics. The \(\Phi ^{6}\) approach is used to obtain an advanced analytical solution for it. The model framework can yield accurate and efficient solutions for various wave structures based on this methodology. By utilising the method, we acquired different behaviours of solutions such as hyperbolic, trigonometric and rational waves. The accuracy and adaptability of the \(\Phi ^{6}\) approach in fractional model modelling are also validated. As a result, this study demonstrates that the \(\Phi ^6\) approach is an effective method for analysing wave propagation in fractional models. The \(\Phi ^6\) approach, which is used in this study to construct solutions, is important in mathematical and physical fields.