Thunderbolt 3 external drive not showing up in Ubuntu 20.04

Question

I have Ubuntu 20.04 I try to add a Direct Attached Storage (DAS) to my Ubuntu machine via a Thunderbolt 3 slot.

The DAS is an "2big Dock Thunderbolt 3 from Lacie".
Via USB it works.
Via "Thunderbolt 3" it is recognized under Devices > Thunderbolt

But I can not access the disk.
How can I make Ubuntu mount the disk?

Answer 1

What helped was

• disable "Security" for Thunderbolt BIOS by
  Setting it in BIOS> Advanced > Chipset Configuration > Intel Thunderbolt
  to "No Security"
• setting the Thunderbolt mode to "BIOS Assist"

After it is listed under Disks on the picture