I think case-insensitive auto completion is actually a setting that you can change in the IDE settings: https://www.jetbrains.com/help/idea/auto-completing-code.htm...

> Match case - Select if you want letter case to be taken into account for completion suggestions. Choose whether you want to match case for the first letter or for all letters.

Also, there are a few interesting plugins that improve the autocomplete in IntelliJ further, such as Codota: https://www.codota.com (language support varies)