Will Using an Ethernet Cable Slow Down Other Devices?

No, using an Ethernet cable will not slow down other devices.

Ethernet will definitely outperform WiFi in just about every way. However, I understand that if your router is downstairs and you're upstairs, it may complicate things. You could look into running an Ethernet cable along the walls or exploring powerline adapters as a solution.

Ethernet is a direct link between your device and the router, so it greatly reduces interference. You typically get better speeds and stability unless you have a really low-quality cable. If your ISP isn't giving you bad service, then you should see significant improvements with a good cable. Just keep in mind some offline games may still require the internet, which could cause you to get disconnected.

Yes, there are tons of factors that can affect your WiFi performance, but switching to Ethernet is usually a major upgrade. You’re right to consider it, especially given the issues you've been facing.

Using an Ethernet cable is likely to solve your current issues. Generally, it shouldn't slow down other devices unless you're downloading or updating a game on your Xbox at the same time. But most improvements in connection stability will come from being wired instead of relying on WiFi.