Hello   @okaoka 

RE650 uses  1 x 10/100/1000M Ethernet Port (RJ45) which will cap the speed coming into RE within 1000Mbps when work in AP mode. 

1733 Mbps the Max Transmit Rate or Link speed of 5Ghz works on 4 MIMO, it requires your device network adapter also support 4 MIMO (more antennas) to get the max Wi-Fi link speed. 

If your VR device supports Wi-Fi6, you could also consider Wifi-6 Model RE which can get 1201 Max link speed when works on 2 MIMO. 

  @okaoka 
Ethernet connection is better (wire range extender to router or switch ) if you expect to  faster speed on range extender 
Range extender works in half-duplex mode when wirelessly connects to AP and link speed will cut to half . Plus wireless loses  more speed on transmission than Ethernet,   an Ethernet connection is still faster than Wireless connection.  Hope this helps.