I want to change the background for specific rows in a matrix. I am able to change the background in the field formatting section background color, but it only changes for the values, not the row header. Is there any way to also change the row header background color, but only for specific rows?
Based on my test, it is not possible to meet your requirement currently. You can come up a new idea about that and add your comments there to improve Power BI and make this feature coming sooner.
Sorry to hijack, but this shouldn't be a new idea... this is more of a bug report. Why? Because you can apply the field formatting to the Matrix Value Header if you don't have Values as Rows selected. but once you use the "Values as Rows" option (from the Value styling subsection), the row headers don't get styled like the column headers do when using this Field formating tool.
It would be nice to get this fixed sooner than later, and we shouldn't have to submit an "idea" for it, since it is implied that this functionality already exists (works for columns headers, so why not row headers?)