I'm cc'd on this thread from a while ago when I was looking around for solutions to the many issues that plagued my XPS 9300 laptop and my WD19TB dock (same combination as OP here). I can state that with any Linux kernel 5.10.16 or later, and XPS BIOS 1.5.0, and dock firmware 01.00.15.01, all problems are fixed. I use that combo daily (although up to kernel 5.12.2 now on Arch Linux) and never get any problem at all which is surprising actually given how flaky it was beforehand. There were a heap of i915 patches done in 5.10.15 which are required and then 1 more from 5.10.16 (Fix vswing programming for TBT) that is essential.
I'm cc'd on this thread from a while ago when I was looking around for solutions to the many issues that plagued my XPS 9300 laptop and my WD19TB dock (same combination as OP here). I can state that with any Linux kernel 5.10.16 or later, and XPS BIOS 1.5.0, and dock firmware 01.00.15.01, all problems are fixed. I use that combo daily (although up to kernel 5.12.2 now on Arch Linux) and never get any problem at all which is surprising actually given how flaky it was beforehand. There were a heap of i915 patches done in 5.10.15 which are required and then 1 more from 5.10.16 (Fix vswing programming for TBT) that is essential.