w00t. After my first order getting utterly messed up, the OWC Thunderbolt 4 cable I bought off BozosPenisRocketsAndBridgeDemolition.com arrived today. Careful readers will note I bought a TB3 dock and not a TB4 one, but I still elected to get a TB4 cable. I did this for a couple reasons: First as Grawk mentioned in Jacob's Jacobless Jacobing, The TS3+ and TB docks in general are picky AF about wires. Secondly, I might end up with some TB4 devices in the future.
The utter lack of drama in connecting the TS3+ dock was lowkey impressive. *boop* Power connected. External monitor comes to life. Turning off WiFi and the gigabit ethernet does what it says on the tin. I have not tested the optical digital output yet, largely because I cannot be arsed to dig up a cable of sufficient length and run it behind my desk.
TL;DR: If you're going to make use of a Thunderbold dock, do not skimp on the cable. The OWC branded one I bought was about $60 shipped, and was much better reviewed than the sea of Chinesium ones that ranged from $15 to $40.