I imagine you’ve already read the apparel mega thread but I’ll include the link just in case.
https://www.wgt.com/forums/t/661183.aspx?PageIndex=1
You don’t have to worry about whether distance items are stackable because there aren’t any instances where the same boost is found in different apparel categories as follows:
Driver distance - caps only, Swing Edge only
3W distance - shirts only, Max and Swing Edge
Hybrid distance - caps only, Foxwind only
Iron distance - shirts only, C&M, Foxwind and Topgolf
Wedge distance - pants only, Foxwind only
There are instances where other attributes such as surface power, precision, sweet spot etc could potentially be stacked but honestly these attributes are so subjective that it is impossible to tell whether they are having any effect at all.