Hi Bo,
I see two options for this:
1) You can retrieve the report data in excel using the REST API. I once tried this here:
https://community.webcon.com/forum/thread/109?messageid=109
I got stuck transforming the result though. Maybe you have someone who knows Power query to get this to work. In addition you would need to execute the request multiple times if you have more than 1000 rows.
2) Direct access to the SQL server to retrieve the data in Excel. Of course this has drawbacks like, security, parsing of picker fields and so one but you can work around them. For example creating creating new views and granting access to them. Maybe they can be moved to another database all together.
If they don't need realtime access you could periodically store the data as a CSV file. This could be a starting point:
https://daniels-notes.de/posts/2021/report-subscriptions
The biggest difference would be, that you don't send mails but create CSV files.
Best regards,
Daniel