What components should I upgrade for better gaming performance?

Definitively the CPU! But keep in mind, that will mean you'd also need a new motherboard and possibly new RAM. Given the games you play, I don’t think your GPU needs an upgrade right now. Stick with your current 16 GB RAM set up but make sure you're using them in dual-channel mode for better performance. If you want to stay budget-friendly, check out 11th or 12th gen Intel CPUs; you’ll need an LGA1700 socket motherboard. Researching reviews on sites like Newegg can help you find good options and use PCPartPicker to find the best deals.

I'd say the CPU is the first thing you should upgrade since it's older and hitting 100% is a clear sign that it’s struggling. You might not need to upgrade your GPU yet based on your gaming style. Just ensure your RAM is in dual-channel mode for the best performance. Surprisingly, I’ve seen people stick with 16 GB for quite a while, but if you want future-proofing, consider moving to 32 GB.

Honestly, you'll probably want to upgrade the CPU since it's an older model and if it's hitting 100%, it's likely bottlenecking your performance. Just keep in mind that upgrading your CPU will probably require a new motherboard since Intel changed their sockets starting with the 11th gen. And if you have DDR4 RAM, you might want to look into switching to DDR5 or at least get more RAM if you can afford it. That said, if your GPU is still performing fine, you can hold off on that for now and consider upgrading in a year or so.