Hello @Bryan_Zeigler !
Are you including a lot of calculated fields in your pivot table that are being totaled, and are those calculated fields on the analysis level or the data prep level?
Pivot tables do have limitations such as row and column limits and a max of 500,000 records. Once you start to approach those limits it can cause things to slow down because it loads more computations on the dataset/source.
My recommendation is consider breaking up the pivot table if possible or adding more of the calculated fields to the data prep level.