High-level summary
1. Wifi5 (802.11ac) standard is only 5GHz band. Wifi6 (802.11ax) is providing enhancements for both 2,4GHz and 5GHz bands.
2. Wifi6 introduced OFDMA, repviously OFDM was used.
3. Modulation wise Wifi6 supports 1024QAM and wifi5 supports only 256 max.
4. Uplink MIMO and MIMO capabilities were increased in wifi6 standard from 4X4 to 8X8.
5. Wifi6E just ported all the enhancements available in WIfi6 with added support for 6GHz band. 6E supports all 2.4GHz, 5GHz and 6GHz.
