Speeding up NAS 4K streaming Speed

[Pabla]

Ive been using my 5tb Segate (partitioned 4tb and 1tb) drive with my rt-ac3100 as a time machine back up and a media server. Recently I've been uploading a few 4K higher quality movies, roughly 20gb in size, and every time I try to locally stream it, say on my Apple TV 4k off of VLC, the stream is very laggy. Audio is fine but video keeps dropping frame rates. Currently I am using the drive in the USB 3.o port, but its set to USB 2.0 mode that's the only way the drive shows up. When streaming I'm using the upnp protocol as well. Ive tried on my Xbox One X as well and same thing, I've also tried wired and wireless connections and that doesn't help either. Does anyone recommend any settings that I can adjust so that the streaming capabilities can be better? Maybe using a different protocol? Or am I pushing the router past its capabilities.