Linux (unRaid) is somehow blocking the device on the host.
I found out that you can unload the bluetooth drivers and it works now inside the VM.
modprobe -r btusb
modprobe -r bluetooth
If you want that it persistent between reboot, you have to blacklist these drivers.
Normally it is /etc/modprobe.d/ but unRaid does not replace the initial root filesystem (initrd / rootfs) with a block device so changes where are not persistent.
In some other forum thread a found something like this for unRaid. (not tested because my system is still running)
[6.10.0-RC1] Onboard Bluetooth no longer able to passthrough to VM
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This One Is really working for me Thank you for your Guide