Thanks to everybody for their replies thus far.

As I have continued my research I found this interesting website:
https://deutscheslied.com/

An impressive archive of German folk song material.
It seems this archive is the passion project of one person...a man of German heritage from/living in Canada.

Most definitely an impressive effort.
He also has a YouTube channel, where he posts recordings.
https://www.youtube.com/channel/UCUPr7Nm-uBwiLbuyQVfE7xA/videos