Hi Zuzana, although this is not straightforward, it is possible to use
M:N relation to map facts in fact dataset in single currency to different currencies. Bridge table which implements mapping between source currency and target currency may contain foreign currency exchange range which can be used in MAQL formula to convert data from fact table in source currency to target currency. Adding target currency attribute into a report would lead to data duplication and data would be displayed in multiple currencies. This can be combined with data permissions to filter data for the user and display only single target currency.
Another option is to store data in fact table redundantly in multiple currencies without M:N relation in data model and use data permission to filter data in given currency for the user.
An option can be also to replace data permission with some mandatory filter in UI which would filter always single currency. This can be probably implemented in some custom UI and selection of the currency can be then sent as one of the filters of executed insights/dashboards.
You may also consider using of custom dashboard plugin and render custom table with reordered columns or merged value with currency. In edit mode of the table you would see currency and value as separate columns but users of dashboard would see them formatted according to your needs. see
https://www.gooddata.com/docs/gooddata-ui/latest/references/dashboard_component/dashboard_plugins_api/
Although the dashboard plugin is another workaround, I am afraid that I do not have a working example of this as plugins cover a wide range of use cases, but you may consider it as the optimal solution.
If you are interested in reading further, this question was also raised in our Slack Community where one of our engineers step in with some workarounds:
https://gooddataconnect.slack.com/archives/C01USCF4S10/p1654090749547249
I hope this helps, but if you have any questions or concerns, please feel free to let us know.