I've recently bought a Mac Studio, Studio Display and 8TB LaCie d2 Professional external hard disk from Apple Store to eventually replace a 2017 iMac. The Mac Studio came with Sonoma pre-installed so I continued to use it.
I connected the Studio Display to the Mac via the Thunderbolt cable and connected the LaCie disk to one of the downstream USB-C sockets on the back of the display. I use the LaCie disk mainly for Time Machine backups.
I've been steadily installing my apps and transferring my files across, having found that the change from Intel to M2 Max processor was possibly one step too far for the Migration Assistant. (I use Parallels Desktop and Docker Desktop and these didn't migrate well between processor families).
I've noticed a certain amount of "flakiness" in the operation of the new computer. Little things like mouse right-click didn't work reliably (Fusion360), my Bluetooth devices were forgotten, Time Machine got stuck and program settings weren't being saved between sessions. The final straw came when I couldn't enter my password to unlock the screen saver and had to forcibly power the computer off. Having found this thread, I tried downgrading to Ventura but found little or no improvement in behaviour.
I think the flakiness may be linked to unreliable disk I/O with the LaCie disk connected via the Studio display so I have moved its cable to one of the Thunderbolt connectors on the back of the Mac Studio. It's early days so far, but the system seems much more stable now.
I hope this helps.