Blank cells in crosstab not converting to 0 despite IfNull / Coalesce all being tried

Issue:
I have a Matrix Grid showing "Work Time" by Worker (rows) crossed with Activity Date (columns). For Worker + Date combinations where there is no underlying fact record (i.e., the worker logged no activity that day), the cell renders as blank/null instead of 0.

Example: in the attached screenshots, several workers show blank cells for most dates, with a value only appearing on days where activity exists. I need these blank cells to display 0 instead.

What I've already tried (all unsuccessful — cells remain blank, not 0):

1. IF([Measures].[DAILY_USER_SUMMARY WORK_TIMESPENT] > 0, [Measures].[DAILY_USER_SUMMARY WORK_TIMESPENT], 0)
2. IfNull([Measures].[DAILY_USER_SUMMARY WORK_TIMESPENT], 0)
3. If(IsEmptyQuery(), 0, [Measures].[DAILY_USER_SUMMARY WORK_TIMESPENT])
4. Coalesce([Measures].[DAILY_USER_SUMMARY WORK_TIMESPENT], 0) → ran without error, but cells are still blank, not 0.
    

Can you please guide to me solve this in Formula 

Thank you