Channel and Bandwidth Impact on csi

[rack570]

Hello, I want to detect the human count through csi. So thank you for creating this tool. But before I start, the channel and bandwidth went into the input, so I wonder what this impact is. What I'm curious about is..

1. My router supports 2.4 GHz, 5 GHz. Is it csi for 5GHz if I go beyond channel 14?
2. What's the difference between 2.4GHz csi and 5GHz csi? Or should I base it on channel and bandwidth regardless of this?
3. I heard that bandwidth can increase the resolution of the data. Then, in the case of channels, is it appropriate to use channels without other interference to sense? Is there any channel you want to recommend?

Thank you in advance for your reply.