QGIS Exporting Line Direction Symbol from Labels

I have set up certain labels to show the Line Direction using the Line Direction Symbol in Label Formatting, with default < and > symbols. It works great, but I now want to export these symbols for use in a web map.

I have set both the Left and Right directions to ‘Store in Project’ but when I check the Auxiliary Layers they don’t contain any features and just show NULL in the attributes table. The layers are set as Text Edit in the attributes From. I was hoping to use the field calculator to pull the Auxiliary data (< and > characters) into the main database for export.

I’m not sure what I am missing, any ideas? I am using QGIS V3.10.10