How to work with a complex query in BigQuery?

I have a query with about 1300 rows and 260GB of memory usage and when I run it the script can run for hours.

I need this data, I want to process it, use it somewhere else, visualize it but query is too complex.

How to properly work with such a large result and optimize the query execution time.

I don't have the opportunity to use partitions and clusters everywhere, but if I use them where I can, the memory usage becomes 190GB.

Thank you!