In May 2021 I heard from April who had a Dell Wyse 3040. Her version was fitted with 16GB of flash. As part of her exploration of the thin client she had tried out Windows 10.
I can confirm that Windows 10 does run on this, although, with only 16GB of flash on board, you will need to install it on an external device. (I used an SSD paired with a USB adapter). There don't appear to be any working sound drivers for the 3040 in the standard Windows 10 installation.
It's very slow, but it does run.
Any comments? email me. Added May 2021