Part of a cell can be formatted. Why can’t a macro conditionally format the result of a formula?
You can apply a Cell Style only to a whole cell by a formula or by the Conditional Format feature.
I suggest you to use adjacent cells for differently formatted contents. Use white (or other) background color for eliminating the grey grid lines and use border lines, and a desired alignment for a “single cell like” appearance. You can apply it for cells located in one column, or in one row, or in a two dimensional cell range.
Seems same issue in excel. Excel VBA solution: Formatting Text Bold within a formula | Page 2 | MrExcel Message Board