Is it worth even upgrading?

I'm considering upgrading a couple of parts, but not sure exactly what I should upgrade to, or if it's even worth it?

Monitor is: LG 34" Ultrawide main monitor and Dell 32" monitor as secondary

CPU: Ryzen 5 3600

GPU: Sapphire Nitro Raedon RX 5700 XT

Motherboard: MPG X570 Gaming Plus

I feel like I've been bottlenecking but can't figure it out. I've been having some weird frame rate drops when I'm playing games like Delta Force and Deadlock.

Open to suggestions! I have also considered just building a new PC but I don't wanna pay that much and would rather just upgrade.