I just update my Mac Mini M1 to Sequoia 15.0.1. After this the NVME1 drive (PCIE interface) on the Trebleet TB3 Mini Dock mounted normally, however the NVME2 drive (USB interface) did not mount and was not visible at all in Disk Utilities etc.
I transfered the NVME disk to a different Hub (Qwiizlab) and it mounted normally.
Prior to this running macOS 14.x there had been no problems with the Trebleet TB3 Mini Dock at all with good read/write performance to both NVME interfaces.
It seems there is some must be some incompatibility between Sequoia and the USB over TB3 interface. My Trebleet TB3 Mini Dock is running Firmware Version 68.1