This is really encouraging to read.
I had a MacBook Pro with M4 Pro that I had upgraded to macOS 27 DB1. Last week I was given two LG Ultrafine 5K displays and I could not get them both to work using my Dell WD19TB dock. By happenstance, I had already ordered a new WD25TB5 dock and a MacBook Pro with M5 Pro, so I thought surely I’d be able to use Thunderbolt 5 to take advantage of the bandwidth needed to drive two 5K displays. But they still won’t both work, connected to the new dock or directly to the new MacBook using ports on opposite sides of the laptop. I get one display, generally whichever gets plugged in first, while the other gets detected as a Thunderbolt device but not a display.
Notably, the new MacBook needed to get upgraded to Golden Gate by Migration Assistant, so I never tried these two displays with Tahoe. Also, when I connect the dock to my Windows laptop (Dell Pro 14 Premium), both displays light up beautifully.
I think there are issues with the Golden Gate thunderbolt stack.
