PC hardware is not as simple as plugging and playing like a console is. Like you already demonstrated to yourself, it is completely possible to limit performance by not configuring hardware to perform at their rated specifications. Enabling the XMP profile in your BIOS is an extremely basic tenet of building a gaming PC. Your "as is" was you running your RAM at whatever arbitrary JEDEC spec your motherboard automatically set, which can decrease performance dramatically when compared to the XMP profile spec (which is technically an overclock).
It doesn't matter that you exceed the game's recommended hardware. You have lower than desirable FPS and there is a lot of knowledge building you can do about how your 5900x interacts with different RAM configurations, speeds, and timings and how to maximize performance on a game-by-game basis.
If you doubt that fast RAM has a significant impact on average and 1% low FPS in 2042, check out this CPU/RAM benchmark that Hardware Unboxed ran for 2042 back in November, when the game was far less optimized on the CPU/RAM side of things. You can see that a 5950x paired with 3000mhz CL18 ram was able to receive a staggering 18.1% boost to the average framerate just by increasing the speed to 3200mhz and lowering the cas latency to 14. An 18% boost in average frames is what you'd expect from a GPU upgrade, so this should tell you how impactful fast RAM is for 2042.
Your 5900X should be more than capable of handling 3600mhz RAM with cas latency at least as low as 16; some higher binned chips may even be able to hit 3800mhz and keep the Infinity Fabric ratio 1:1.