@FURRYe38 is correct. The RBR50 WAN port is gigabit Ethernet. The maximum actual throughput on a gigabit Ethernet port is slightly more than 900 megabits per second. There is overhead which consumes part of that theoretical speed and there are 'gaps' between data packets. This is true for any Ethernet connection. i.e. a 2.5Gbps port will not actually achieve (literally) 2.5Gbps.
For the RBR50 system, the bigger issue is that it is a WiFi5 system (802.11ac). This limits the maximum speed of WiFi connections compared to WiFi6 (or WiFi6E or WiFi7)
Considering that it takes only about 25Mbps to stream 4K video, WiFi5 provides plenty of capacity for most users. And, most users have mostly devices compatible with WiFi5 (or with 2.4G WiFi).
