Docking station for Dell 7780

You'll need to define the term "bottleneck" and be more forthcoming with what you want the dock to do.  No dock will power the 7780 -- you will need the power adapter plugged directly into the system, as no Thunderbolt dock can supply the power requirements of the system.

Beyond that, what you need depends on what you plan to connect to the dock - high resolution monitor, or just ordinary keyboard/mouse/printer/scanner peripherals?

The WD22TB should handle most requirements excepting the power supply to the system (it can only supply 130W, where the system needs 180 or 240 W depending on the GPU you have.  The same restriction will apply to any other currently available dock until Thunderbolt 5 arrives in new systems and docks sometime in 2025.

Thank you for your quick response.
I need at least stable 1Gb/s in LAN (streaming data from 3D scanner) + two connected monitors + minimum 2 USB 3.0 ports.
The system will need full power due to heavy CPU and GPU utilization. The dedicated power supply is 240W.
The system is WIN11 Pro, if that counts.
GPU is ADA3500

The WD22TB4 checks all those boxes except the power to the system.  As above, you will need your AC adapter directly connected to the system itself.

https://www.dell.com/en-us/shop/dell-thunderbolt-dock-wd22tb4/apd/210-bdqh/docks

Thanks.
What do you think about WD19-240W USB-C (210-AZBW)? Is it compatible?

It will have the same power limitations (it can only supply 130W), so you'll need the system's AC adapter directly connected.  The video capabilities are reduced vs a true Thunderbolt dock - be sure your intended monitor resolutions will work with this dock.

Dell Precision 7780 like other Dell Precision models 7X40, 7X50, 7X60, 7X70 are using Dell Performance Dock WC19DC or WD19DCS.  Latest revision is S which is without 3.5 mm jack.

WD19DC / WD19DCS comes always with 240W charger. Never use smaller chargers with WD19DC / WD19DCS.

WD19DC / WD19DCS has two USB Type-C cables. Light must be on in both cables. Each cable provides 90W to your laptop.

https://www.dell.com/en-us/shop/dell-performance-dock-wd19dcs/apd/210-azbn/docks

Remember to keep the PC BIOS and dock firmware up-to-date. You now Dell Command Update?

Dell Dock WD22TB4 can be used with Dell Precision 3XXX series etc. and with Dell Latitude models.

I was just about to post, but, upon looking, it seems that Dell/EMC has released their 1st generation of THUNDERBOLT 5 DOCK in the last 72 hours.

https://www.youtube.com/watch?v=CCG5ROC8kGU

Dell/EMC PN# SD25TB5 

300 watts in a single ThunderBolt5 USB-C connector.

That should get the juices flowing (and, depending on the DC amperage, lock up the muscles for a spell >:} )

It will on a system with Thunderbolt 5 support -- of which I do not think there there are yet any, and certainly not your Precision 7780, which is Thunderbolt 4.

I am succsefully running 7780on WD19DCs (dual USB-C cable ) with 240W power block. Running 2 28 Inch mon on 4K res.

I found the best to be a TobenONE DisplayLink Docking Station 4 Monitor  with 4 HDMI,18-in-1 Quad/Triple4K@60Hz Display Dock...