I install from scratch OMV5 and i don't like, how transmission plugin migrate to docker image.
In OMV4 i download a torrent, move file to another drive and make a softlink , so i have an unfragmented file, use another drive to store it and also seeding it.
But with this disgusting docker image transmission can't take files on softlinks!
So delete docker , install native transmission-daemon from debian and now all work fine.