Planning for complex designs is tough! Interactions can often be smaller than simple effects, and uncertainty for interactions is generally higher than for simple effects.
One useful tool to explore is https://intxpower.com/. The website and lots of useful information about planning for complex designs is described by the creators in this paper: (Sommet et al. 2023).
References
Sommet, Nicolas, David L. Weissman, Nicolas Cheutin, and Andrew J. Elliot. 2023. “How Many Participants Do I Need to Test an Interaction? Conducting an Appropriate Power Analysis and Achieving Sufficient Power to Detect an Interaction.” Advances in Methods and Practices in Psychological Science 6 (3): 25152459231178728. https://doi.org/10.1177/25152459231178728.