direct query gives an issue saying the visualization is taking too long to process
If your database requires more than 2minutes to execute a query, then it will timeout in QuickSight. here is a similar post and possibilities to resolve ( Direct Query with Parameters Timeout )
Run the same query in your database and check the time required and then look at optimization either by scaling the datawarehouse , maybe define a timeframe in the where clause additionally to reduce scanning of data .
Kind regards,
Koushik