How can I delete files on my WD My Cloud drive from my Mac, if WD Apps are not working?

My Cloud OS 3 Personal & Network Attached Storage My Cloud
1

After upgrading the SSD on my iMac WD Sync and all the other WD Apps for Mac are not working anymore (see https://community.wd.com/t/wd-sync-no-longer-works-on-my-imac/243859). As my WD My Cloud drive is almost full I would love to delete most files on it. I mounted it as SMD Drive in the Mac Finder, which works fine. But when I try to delete folders, most of the time I get an error message, that certain files couldn’t be deleted, because they are in use, which can’t be true.

Any idea what I can do to batch delete a lot of folders from my Mac?

2

I managed to delete the files by login in via ssh on my Mycloud drive. From the terminal I could then delete all the files via a simple “rm” command. Now the files are deleted, but I have another problem: Although the files are deleted, the space on the cycloid drive was not freed, it’s still taken. If I look on the web dashboard half of the space is taken my “other” files… Is there a kind of trashcan or so in the drive, that I can delete? Or anything else I can do?