Lightroom Downloader very slow

Hello and a happy new year,

I'm trying to download my Lightroom photos with Lightroom downloader, Version 1.0.5-20220504.116-64f8d2b.

My photo library contains ~69k photos with a total size ~ 890GB.

When I start Lightroom downloader, after giving a brief summary of the library, it starts with 'initializing download...'. The UI shows the name of the file processed at a rate of 1 file per second. That would be an estimate of ~19h for all 69k photos. 

After 36h I stopped the downloader, reboot my MacBook Air M1 and started again.

There is no indication nor estimation of the overall process. I'm missing a bit logging and documatation on how i can estimate a download of a large photo library. 

My conclusion now is that the downloader is buggy as it takes ages for the download of a moderate photo library.

Does anyone have ideas or can point to proper documentation?

Thanks in advance, Claus