Is My CPU Bottlenecking My 5070 Ti?

Hey folks! I'm beginning to think that my gaming rig might be facing some CPU bottleneck issues, and I could use your input before making any costly upgrades. Here's the setup I'm working with:

- CPU: AMD Ryzen 9 5900X
- GPU: RTX 5070 Ti
- Platform: AM4
- Main Game: ARC Raiders
- I game on a 1080p 240Hz monitor, with a second monitor running at 144Hz.

I'm only hitting about 90 FPS in ARC Raiders, which is playable, but I expected better performance from the 5070 Ti upgrade. The in-game FPS overlay often shows that I'm 'CPU-limited', meaning tweaking graphics settings probably won't help boost my FPS.

Looking at my frame-time stats:
- GPU (ms): ~3.0-4.0 ms consistently
- CPU – Game (ms): ~8.0-13.0 ms consistently
- CPU – Render (ms): ~6.0-7.0 ms

The CPU – Game time is always at least double the GPU time, which suggests my GPU is sitting idle waiting for the CPU. My usage stats (courtesy of MSI Afterburner):
- GPU usage: ~30% at low, ~50% at high
- CPU usage overall: ~40-70%, albeit I'm still figuring out MSI Afterburner. The first few cores show about 70% usage.

I've noticed some occasional stuttering and FPS drops that can be distracting. With all that in mind, I'm on the fence about making a trip to Micro Center. My main questions are:

1. Am I genuinely CPU-bottlenecked?
2. Would upgrading to a Ryzen 7 7800X3D and switching to the AM5 platform realistically resolve this issue?

I thought 90 FPS was decent, but after getting the 5070 Ti, I expected a bit more from my system. I'm aware that I'm still learning about the ins and outs of avoiding bottlenecks in gaming. Any insights, confirmations, or reality checks would be super helpful. Thanks!