Hi @frixel ,
Could you provide the details of the error message?
You could refer to the configuration below to create a Flow.

Expression reference:
formatDateTime(body('Get_file_metadata')?['LastModified'],'yyyy-MM-dd')
addDays(utcNow(),-30,'yyyy-MM-dd')
In addition, List files in folder action only returns 20 items. Currently there is such a restriction. If you want to increase the limit on the number of files returned, please consider voting for similar ideas:
List-files-in-folder-on-OneDrive-without-limit
Best Regards,