Is it better to upgrade my PC or buy a new one?

Honestly, it might be more worth it to just get a new PC. Upgrading to hardware that’s already getting a bit outdated doesn’t feel optimal. But if you’re set on upgrading, I've noticed the 9600x is only about $10 more than the 7600x – might be a good deal to grab it quick. Good luck with your decision either way!

You won’t be able to go beyond the 5000 series with that B450 motherboard because of the AM4 socket. Switching to AM5 means you would need a new CPU, motherboard, and RAM which can be costly. Most people find themselves at the top of a socket waiting for a significant performance jump to justify the expense. I suggest getting a new GPU first, and then maybe upgrade the CPU to a 5700x later on. That combo should keep you going for another couple of years before considering a full new rig.

You can definitely swap out the GPU without hassle since the PCIe x16 slots are pretty flexible. But, if you want to upgrade your CPU, you need to stick with one that's compatible with your motherboard. Your B450 supports AM4 Ryzen chips, so you could go for a 5600, 5700, or even higher models up to the 5900. If you were to go for something from the 6000 series, you'd need a new motherboard and RAM too. My suggestion? Start with the GPU upgrade, try it out for a week, and see how much you like it before deciding on any more changes!

You’ll likely need to upgrade your RAM, motherboard, and possibly the power supply if you're changing out both the CPU and GPU. If you can afford it, I think an upgrade makes sense. I had a similar situation in the past, and the improvement I've seen since upgrading has been huge.