I’m new to PC gaming—what should I upgrade first on this hand-me-down PC?

This is still a good 1080p machine and should handle 1440p reasonably well with sensible settings. The 3060 Ti can run modern games at high settings, although ray tracing and very demanding new releases may require compromises. Try the games you actually play before buying anything; frame-rate monitoring will tell you whether the CPU or GPU is holding you back.

For now, I’d prioritize a CPU upgrade only if you want higher minimum frame rates or play competitive games. Otherwise, save your money until the graphics card becomes the clear limitation.

The Ryzen 7 2700X is the weakest part of the system for gaming. The RTX 3060 Ti and 32GB of RAM are still quite capable, so I’d use the PC as-is first and see whether your actual games are CPU-limited. If you want an inexpensive improvement, a Ryzen 5 5600 or 5600X is a strong value upgrade. A higher-end gaming chip such as a 5700X or an X3D model can help with high-refresh esports games, but only makes sense if the price is reasonable.

Update the motherboard BIOS before installing a newer processor, and check that the board supports it. I’d keep the current motherboard and memory rather than replacing the whole platform just yet.

A used Ryzen 5 5600 or 5600X is probably the best low-cost path. Even though it has fewer cores than the 2700X, its newer architecture gives it much better gaming performance. You already have enough RAM, and changing the motherboard would add cost without providing a major benefit immediately.

If you later move to a substantially faster graphics card, then consider replacing the power supply as well. When changing power supplies, use only the cables that come with the new unit—modular cables are not necessarily wired the same way.

For a longer-term upgrade, an X3D processor compatible with the board can extend the life of the system, but don’t overpay for one. The 3060 Ti is still the part I’d keep for now. Upgrade the GPU later when you want better 1440p performance, more video memory, or stronger ray tracing, and check power requirements before choosing a replacement.

Also inspect the cooling and temperatures. If the CPU cooler has old or dried-out thermal paste, cleaning it and applying fresh paste may improve temperatures, but it won’t replace the benefit of a newer processor.