Renars here from Matrixify (Excelify).
Sorry about replying in English here and thank you for suggesting the use of Matrixify (Excelify) @toooru .
You sure can export all item IDs with our app, including the Customer ID.
The process in the app is really simple - on the app’s Home page create a new export, select the “Matrixify: CSV” format to export to CSV file.
Then select to export Customers and Basic Columns under Customers - and export the file.
In the exported file you will have the “ID” column for each Customer with that Customers’s ID.