Perhaps you meant CAT6A? These are spec’d for up to 10Gbps and 100m (500mhz). Whereas CAT6 can deliver similar performance but only up to 55m (250mhz) - I’m sure it’s possible to match the performance but if you’re looking at 10g speeds, it’d be best to go 6A (fiber would be my recommendation). 6A will also be shielded adding to the overall diameter.

Here’s a great article that breaks down the different cables: https://www.cablek.com/fr_CA/cat5-vs-cat5e-vs-cat6-vs-cat7-vs-cat8-what-are-their-differences

WiFi 6 vs 6E. The biggest difference is the 6GHz bands. If you have devices and or a need for 6GHz sure otherwise 6 works fine or you can always wait but there will always be something in the future.