OK this support page
How do I use USB to connect my Roku® streaming device to a wired network? | Official Roku Support Un...
Specifies this adapter is fine with Express 4K
UGREEN Ethernet Adapter for Chromecast and Fire TV Stick USB to RJ45 Lan Network Adaptor with USB 2....
But the Amazon page says
"This Micro USB Lan Adapter is NOT COMPATIBLE with Now TV Stick and Roku Express 4K."
So is it or is it not OK?
On the US page a user stated that it worked "perfectly" with the Express 4k+.