Filtering query data by expression

Grafana v9.5.1, Centos 7.9, Datasource Prometheus 2.43.1

I’m trying to figure out how to filter out data frames from a query result. For context I am using node_exporter metrics, and I start with the following query:
This works, but I have 500+ instances and I would like to only display timeseries where there is a notable drop in the fork rate. Something like this expression I think:
delta(node_forks_total[2w]) < -1000
At this point I think I might be missing some terminology or a core visualization concept. What is the best way to accomplish filtering on an expression like this?