What can I read from these Insights and stats to optimize my game performance?

I’m not familiar with optimization, not sure what can I read from these stats. Anyone familiar with profilers know what I could do to optimize my game?

Current status: 3D FirstPerson Project aim for Windows platform only.
Develop environment: UE5.6 with RTX4070 and 32G ram

Performance:
45~50 FPS when Play In Editor, package build exe around 45 FPS, in some cases around 30 FPS or lower.

Here’s Stat Unit:

This is Stat RHI: around 58 FPS, but in the simplest part of level

Stat GPU when in 40 FPS, and also triggered a crash dump:

Insights: Only under first 1 minute recording. There’re some surge in the back when an NPC spawned.

a 16ms when 58 FPS:

a 177ms frame when in the surge part, around 5 FPS

There’re a lot of WaitForWork or WaitForTask , what are these mean? Seems they’re in the CPU part, where should I look into to optimize the performance? I’m currently on UE 5.6, heard this version already have optimized some performance. How to utilize this optimization?

Thank you very much!