Slow uploads easybackup ftp

[osfast]

SO im having a challange with easy-backup (the minecraft plugin) and the developer seems to shove it on the pile of "its a ptero problem" but it might just be so im wondering if you guys have some tips or ideas.

When the plugin makes the backup (zip) its done in like 5-7 minutes (about 7 gig) but when it stars to upload that to the nas (same network bigger storage) its gets super super duper slow and takes about 7 hours to upload via ftp.
When trying to upload the file via ftp from the server console its super fast again (like 10 min or less) but running from the minecraft container is so so slow.

I checked the settings and i could initially find something that limits the upload speeds. but i might have overlooked something.
Is this a ptero/docker thing or a easy-backup thing? does anybody have the same problem or might know a solution?