Chromium 92 and later failed to download files if the ~/Downloads is a symlink to another file system (FS). Chromium spits message "Failed - Download error" and creates a Unconfirmed 56679.crdownload in ~/Downloads directory.
Apparently, Chromium-92 is able to write to the destination directory, but does not like it somehow.

How to repeat:
Using two file systems: /home and /data (or /tmp)

mkdir ~/xyz
ln -s ~/xyz ~/Downloads     # this works because Dest directory is on the same FS

rm ~/Downloads

mkdir /data/Downloads
ln -s /data/Downloads ~     # this makes Chromium downloading failed because Dest directory is crossing the file system; Chromium 78 and earlier version work well on across file system.