The question needs more precision : is it the cluster startup that takes a while ? If yes, try serverless warehouses
Are there many queries running in parallel and that is where you see a slow down ? Each cluster can only run 10 queries in parallel, so in that case you might need more clusters.
Overwise, maybe just increase your cluster size, or refactor your query. Check what step is taking a long time by going to Query History and see each steps performed by the clusters.
