Upload and Download speed on Xbox shows "Not Available" and affecting performance on Xbox...

Call you ISP and get them to look at your connection and hardware remotely. They might help you with the network hardware settings that may be missing after you factory reset it.

Usually all that's required with network hardware is a power cycle to reconnect to your ISP and the XBLive.

Try Network settings support and click on MTU issue of Connection
error solution to change firewall settings

Firewalls within your network hardware are intended to help secure your network by restricting the information that travels between your devices and the Internet. However, you may experience connection issues if your firewall is restricting necessary traffic
(a setting which may be blocking your Xbox One from connecting to Xbox Live). Additionally, some firewall settings, such as IP flood detection, can cause connection issues.

If your using WiFi to connect to your network hardware, try a wired ethernet cable connection instead.

If you are already using wired, check your cable and make sure they are firmly seated in their respective sockets.

Connection solution support has further assistance to guide you.

I would maybe hard reset your xbox

I reset my router before back to factory settings by holding and pressing the "reset" button on the back with a paper clip back to its default state when I first had it installed at my home, shouldn't that also fix some problems? I don't know if this is
any significance but this is what I believed started it:

It was working fine 3 days ago until I had to install an update for Rainbow Six Siege, the update was downloading automatically by itself and at the same time I uninstalled the game, after that, its when I got all my problems.