Ignoring the pointlessness of CPU power when considering that Remote Play is essentially "just" a h.264 video stream with a remote control joystick.
What those CPU requirements are probably effectively mandating is a minimum expected CPU that is required to be able to decode video. The shift from CPU to GPU decoding and improvements in the built in GPU decoder have made those requirements largely moot. A modern phone can easily handle Steam Link and Remote Play duties courtesy of hardware based video decoding.
Basically for effective Remote Play your system needs to be able to quickly decode video at low latency, while simultaneously capturing controller data to send back. Using CPU decoding meant that you really do need a fast CPU to keep the latency down, modern GPUs though can do the same job a lot faster and with a lot lower power draw.
The low latency is key though. If your CPU takes too long transferring data from the network to your graphics card then you might find the lag to be unusable. Your console is using hardware to record the screen, broadcasting it to the other machine and then decoded. Due to this there is a slight delay between you being shown what the console is rendering and your reactions in pressing a button, which then has to negotiate it's way back across the network. It is an ongoing cycle and the encode/decode delay is the difference between "usable" and "unbearable".
Doing both encode and decode stages via GPU hardware can bring the time down to a couple of handfuls of milliseconds at each end, and leaves the CPU available for all the other tasks it has to do already. For controller input response times need to be as fast as you are shown it and leaving the CPU clear of work makes that task a lot easier.
Your connection between the two machines is important as well. Older Wifi routers were quite slow and modern high speed ones, especially with the increased bandwidth and improved latency of 5GHz (due to more channels and less noise/overlap) are a lot better. Not many years ago it was recommended to use wired ethernet if possible, while now wifi is actually usable.
While your system might be slightly lower in terms of clock speeds, it will instead have several generational improvements to the actual CPU core, as well as potential improvements to the GPU, memory and other systems.
It is also possible that by specifying the minimum processors they effectively specify a minimum level of GPU support that is required without having to ask you to go hunt down yet another piece of esoteric information about your system. In telling you you need one thing they mandate another by proxy.
Clock-speed isn't everything.
Chances are your system is fine.
