Edit: A Reddit user has gone the extra mile and uncovered that the phone checks for a Samsung vendor ID on the adapter being used. This is clearly an artificial limitation and one that Samsung should correct immediately. See the output code which indicates this here: https://www.reddit.com/r/SamsungDex/comments/jte853/a_deeper_look_into_samsung_dex_resolution_and/
Easily resolved with root, meaning Samsung can correct it in a future update with little more than a line of code.
Edit 2: Motorola's "Ready For" desktop mode supports up to 4K output regardless of the dock or adapter used (assuming the dock/adapter otherwise supports 4K) as does the AOSP desktop mode. You can even try the latter on a Galaxy device and get up to 4K output where DeX restricts you to 1080p. Ridiculous.
Please do not artificially restrict "smartphones" to only FHD and HD+ resolutions when using an accessory other than a DeX Station or DeX Pad. The Tab and Fold can both display 1440p regardless of the accessory used, and have no such limitation imposed on them.
Please simply allow the same freedom of resolution to all DeX devices, "regardless of the type of connected accessories." Samsung doesn't even make or sell a DeX Station or DeX Pad anymore!
Thank you -
I need 32:9 resolutions and 4K. My foldable phone can output those resolution signals, but dex swiches signal back to restricted ones at last boot up step for no real reason. Pls samsung
Gross anti-consumer behaviour by Samsung locking out 1440p on regular Galaxy/Note devices with an arbitrary software policy.
Seconded. This greatly limits the usefulness of dex to me. I did not know of this limitation before I bought my phone and I would not have purchased if I knew about this beforehand.