This script is relevant to Paperless-ngx up to version 2.11.2. That's because version 2.11.3 added support for a default currency for each Monetary field.

HOW TO USE THIS SCRIPT

1. Make sure your browser can run user scripts. In doubt, just install the Violentmonkey extension.
2. Click on Install this script from https://greasyfork.org/en/scripts/502490-paperless-default-currency
3. Click on the green + Edit button.
4. Edit the @match line, replace https://demo.paperless-ngx.com/* with your Paperless installation. (e.g. https://127.0.0.1:9493/* )
5. Edit the DEFAULT_CURRENCY below to your preferred currency.

See also: https://github.com/paperless-ngx/paperless-ngx/discussions/6040