You have not specified what your
hwsd_csv value is. However, you need to use the name of the data source, not the name of the table view when removing a join.
So, based on the values in the error message, perhaps the following might work:
The documentation at ArcGIS Pro / Tool Reference / Tools / Data Management toolbox / Joins and Relates toolset / Remove Join states:
The join name will not reflect the name of the table view itself, but rather the source of the table view. Therefore, if a table view is named
TableView1 and points at
mytable.dbf, the name of the join will be
Alternatively, you can just remove all joins by not specifying the join name at all: