Your internet connection could be the actual culprit here. Most budget streaming devices like Rokus streaming stick or Chromecast dont have an Ethernet port on them. High-end streamers like Roku Ultra, Apple TV, and Amazon Fire TV, on the other hand, have built-in Ethernet ports in them. If you have multiple devices, trying to connect to the same internet then you might want to subscribe to 50-100 Mbps of internet speeds for ultra-high-definition 4K streaming.”]
Source: https://hackercombat.com/how-to-improve-streaming-quality-on-netflix-and-hulu/