Nextcloud version (eg, 20.0.5) : 20.0.5
Operating system and version (eg, Ubuntu 20.04) : nextcloudpi (debian 10.7 32bit / Linux 5.4.83-v7l+)
Apache or nginx version (eg, Apache 2.4.25) : Apache/2.4.38 (Raspbian)
PHP version (eg, 7.4) : PHP 7.4.13 (cli)
The issue you are facing:
I am trying to download Media from my media server.
To make sharing and access easy I thought I could use the external Storages SMB integration. Which I did and it works great until I try to download something.
I tried to sync a few movies to my pc and it worked for everything except the movies. They downloaded but all have the same size! Nothing bigger than 2097152 KB. Of course all of them are broken, they are much larger…
It should be 14,302 GB
To me it looks like a kind of buffer problem?
My Nextcloud Logs tell me:
[PHP] Error: Unknown: send of 5 bytes failed with errno=32 Broken pipe at Unknown#0
PROPFIND /remote.php/dav/files/Simon/PC/Musik
from 192.168.178.94 by Simon at 2021-01-31T14:20:36+00:00
I am having general problems with up and download and I am thinking of a complete reinstall:
But I would prefer to solve the issues if possible! 
Thanks for every bit of help,
Cheers Simon