There is no "transparent" value for rasters. If it was a simple rgb 0, 0, 0 would be black and 255, 255, 255 would be white. You could define nodata values but it would be assigned a color for viewing, it can't be exported as transparent ... but ...
Export or convert raster datasets—ArcGIS Pro | Documentation
has use render, and force rgb settings that you might want to experiment once you have set a nodata value and symbolized it as transparent (eg no value/color)
... sort of retired...