Client video gallery.

[TribalHound]

I wonder if there is a way you can setup a folder with thumbnail images for them to view that uploads to your website - to each image you embed a video link, so when they click on it , it downloads ?
So instead of currently uploading all the videos you're actually only uploading still images with urls and creating a catalogue. Not sure how many people / how often the watch the clips, so hard to determine the impact on your upload speed. Perhaps the popular one's you upload to your site and the link behind the image points to that instead.

I doubt the solution is as simple as changing the view settings on the NAS folder you're exporting to.

QNAP file station has an option in your 'share link management' folder to Support multimedia playback, steaming and thumbnail display. There might be similar on your Asustor - but I'm guessing that means every video plays on your device and they're just watching it. That could be a huge demand on your NAS.