For PS5 gaming, I'd recommend the LG. The C4 basically has everything you need: 120Hz at 4K, input lag in the low single-digit millisecond range, and OLED technology just gives you better colors and deeper blacks. The Samsung isn't a bad TV either, but when it comes to gaming, the LG just has the edge.
The C4 is known for LG really optimizing it for console gaming. The response times are lightning-fast, and you'll get the new gaming features without any issues. The QN95D is more of a solid all-rounder TV - good for movies, good for shows - but for pure gaming performance, the LG is just the better choice for your PS5.
Sure, the price is higher, but if gaming is your main use case, it's worth it. OLED panels also last a while as long as you're not constantly displaying static images on screen. Check out both in the store if you can - it really makes a difference in how you perceive the picture quality with OLEDs.