Thank you for contacting Plugable support! I’d be more than happy to assist you.
Unfortunately, your existing UD-ULTCDL dock cannot support this display. We do have other docks that may work, but to be fully up front at this time we do not officially support this resolution display via any of our docking stations (as we do not have a similar display here for testing purposes).
With that being said, the total bandwidth required for a 5120x1440 60Hz display is less than the total bandwidth required for 4K 60Hz (the maximum resolution we do officially support). This means that in theory this display can work from a Thunderbolt 3 dock with a DisplayPort output, we just can’t guarantee it.
Please note: In addition to this resolution not being officially supported, we also do not officially support refresh rates over 60Hz, so this Samsung 240Hz display would be quite limited in this particular area by a dock. Though, if not gaming this may be a non-issue for you.
For what dock we can recommend, because we have never tested a display like this it’s hard to make a recommendation with confidence. However, our “TBT3-UDV” may be the best bet: https://plugable.com/products/tbt3-udv This dock offers one DisplayPort output capable of 4K 60Hz, 60W of charging (same as your current dock), multiple USB ports, Ethernet, and audio.
Please don’t hesitate to let us know of other questions.
Thanks again for contacting Plugable support and best wishes!
Senior Engineer | Product Owner