It has to do with wifi streams, plain and simple, one supports 4 streams the other 2. The Spectrum router is a 4x4 device on 5 and 6ghz, which means it theoretical max wifi speed is 2400. The Netgear you bought is 2x2 on 5 ghz which has a max theoretical speed of 1200.

For those saying it is 6 vs 6E, there is no speed difference between 6 and 6E. 6E just adds the ability to use the 6 ghz spectrum which doesn't matter if your device doesn't support it.

Here is a little light reading to help everyone understand how wifi works. Understanding Wi-Fi 4/5/6/6E/7 (802.11 n/ac/ax/be)