BJB
That link you provided and the responses by renojim and atc98092 still provide the info you need. Ethernet still limited to Fast Ethernet (100mbps), though can get likely higher through a wireless (wifi) connection if needed.
QNAP actually has an app for Roku (QMedia) so gives you an additional method to accomplish what you are trying to do.
[Tutorial from QNAP] https://www.qnap.com/en-us/how-to/tutorial/article/how-to-play-media-files-on-a-qnap-nas-with-roku-channel-qmedia
[QMedia app Roku Channel Store] https://channelstore.roku.com/details/d0000ca4601a5bf0ec9ab1aa21a8ec0b:4d53fbd18eda2ca67f27c57202f0245a/qmedia
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If you have a media server on your NAS/hard drive/router, etc, you can still just simply use Roku Media Player (RMP) via DLNA. (launch Roku Media Player, discover your server, and play through RMP).
If you have a media server on your NAS/hard drive, etc, (ie. QTS) and there is an available app in the Roku Channel Store, then can either use RMP, or launch the app (ie. QMedia) from your Home Screen and access your files through the app's GUI interface).
If ever in the future you need something fancier, or with more features, then plenty of Media Servers like Plex, Emby, Jellyfin and others exist that also have Roku apps available (allowing for this additional method to use on your Roku devices).
I generally just use RMP, but my needs are simple and just need to play the files from my hard drives. (hard drives connected to my routers that have simple built-in media servers like miniDLNA). Occasionally I will pull from my Jellyfin server as well, (can do this via RMP or the Jellyfin app on Roku).
