"Trying to divide autistics into groups is surrendering to society's ableist pattern of ostracizing those who are different rather than including them."

Not really. It's more about being aware of people's abilities, the level of support they are likely to need, and being realistic about where they can fit into society and contribute.

For example, the levels as explained here (ASD Level 1, ASD Level 2, ASD Level 3):

https://www.lanermc.org/community/lane-health-blog/the-3-levels-of-autism-explained

Of course, within each category we know there will still be a lot of variation, so it's still important to understand people's individual differences and needs. But for the purposes of allocating support, it can be helpful to have categories like this.

"Instead of attempting to categorize us, it would be more effective to increase awareness of the entire autistic spectrum and the diversity among autistics."

You're creating a false dichotomy there. It doesn't need to be an either/or scenario. We can do both.