The Quick Import tool fails and returns the error message, "Error reading configuration file: filename '%0 does not exist." when the Windows username contains the following characters: ä, ö, ü, õ.
With Data Interoperability for ArcGIS Pro 3.0 final testing, this issue is non-reproducible. The issue fixed for this bug is Github issue #67 which is a similar issue. Issue 67 was fixed with enhanced support for Universal Transformation Format (UTF) released by Safe software with FME ENGINE 2022.0.0 as briefly described in this article: https://community.safe.com/s/article/UTF-8-Names-FAQ-Encoding-in-FME.
This FME Engine is released with Data Interoperability for ArcGIS Pro 3.0. Since this is an FME Engine fix, backporting the fix to ArcGIS Pro 2.9 is not currently under consideration.