Slow write speed on usb 3 hdd when using OMV 6 instead of OMV 5

Hi, I was using OMV 5 on a RPi 4 (32bit Buster) for some time now, and I wanted to upgrade to OMV 6. I started from scratch using the official guide and a new SD card and installed OMV 6 on top of Bullseye 64bit. Now I have this problem: I have two 8tb WD My Book HDDs connected to the two USB 3 ports of the Pi and the writing speed on both drives is around 25 Mb/s. I tested this on both drives with a ssh connection and dd if=/dev/zero of=./test bs=512k count=2048.

When I use my old OMV 5 SD card again, I get writing speeds of around 160 Mb/s.
I tried enabling and disabling the writing cache of the drives, but that didn't change anything. Is there anything I can test or change to fix this?

Idk... after some changing back and forth between OMV5 and OMV6, it now seems to work well with OMV6. I get around 70-80 Mb/s over my wired (smb) network, and that's probably all I can ask for...

I'll tag this thread as solved...