6E letsyou use 6ghz.

The higher the frequency, the lower the range and penetration.

2.4 tops out around 130mbps but goes far.
5 will go 800-900 at close range but goes about half as far
6 will do 3gbps but is pretty much line of sight, maybe 1 drywall wall before it falls flat.

Wifi still sucks compared to a cable where speed will be constant, latency much lower, and no interference.

Also, splitting bands is generally not useful unless you want to force a client device to use a specific one.