Adobe Illustrator and InDesign might share some functions, but they are used for different things which makes direct ai to idml conversion problematic. Users looking for ai to idml conversion are pretty much always do that because of printing reasons as printers often prefer InDesign format over Illustrator.
You can certainly place AI files as objects inside InDesign document (File ► Place), but you won't be able to change anything. Another option would be just to manually copy over data between Illustrator nd InDesign (copy+paste method). Third option is to use PDF as middle format, in which you export your Illustrator with PDF compatibility in mind and import that to InDesign.
It is unlikely some dedicated converter for this exists as it is far from simple file conversion.
Updated: January 31, 2023