Should I upgrade from DDR4 to DDR5 for gaming?

Not really. If you already have a decent DDR4 system, the effort and cost of swapping to DDR5 isn’t paying off in gaming today. Real-world gaming gains are 3–5% at best, and often zero, because games care more about GPU and memory latency than raw bandwidth. You’d spend $400–600 on a new motherboard, RAM, and possibly a cooler for single-digit FPS improvements, while that money would give a bigger boost if put into a better GPU or a cheap CPU upgrade on your existing platform. If building from scratch, go DDR5 for future-proofing, but for an upgrade from DDR4, the hassle isn’t worth it.