How to delete 2.6 GB of Maps data?

Do you happen to have any maps downloaded to your device; maps itself only uses around 100 Mb on my device without offline maps.

You could check inside your maps application; once entered, click on your Apple account picture, and navigate to the offline maps section.

Have a good day; feel free to reach out if this is not the present problem.

Open Maps app > tap your round account icon in the upper right > tap Offline Maps > tap whichever maps you want to delete > select delete.

you can delete the Maps app if you don't use it.