Thunderbolt device not recognized by macOS Big Sur Beta

I'm having the same problem with my Thunderbolt display.

Anybody found a solution to resolve this issue ? I reported this to Apple via Feedback Assistant.

Mine is Promise Pegasus R6 Thunderbolt RAID. Found a post in another forum ... it seems kernel extension/driver for the Promise RAID array wasn't loading. In Terminal executed this command :
sudo kextload -b com.promise.driver.stex
Thunderbolt RAID loaded fine.

This issue is fixed in the latest beta.

I'm also having the same issue after upgrading my Late 2014 iMac Retina 27inch to Big Sur.
I have a 17TB Drobo 5D, connected to my iMac via Thunderbolt, and it doesn't mount normally.
The Drobo drive still exists and been recognized both on Drobo Dashboards and Disk Utility App,
but it simple doesn't Mount.
After re-connecting the Drobo Drive via USB, it worked and mounted normally, so it's obvious that this is a Thunderbolt trouble.
Drobo also announced this issue officially on their website.

Is the problem still relevant 4 month later February 2021 ?
Can't get any connexion of my 3 Promise Pegasus RAID towers.
Is there any Apple patch as I don't found any Promise update !!!
Need my old DATA & backup