You said that my "question suggested that the amount was important in the discussion." But that was not my intent. What I said was that I would want to make valid comparisons. You say that "when you have enough or too much RAM available the amount doesn’t matter after a certain point," which is true.
However UMA RAM operation is very different, and probably evolving. E.g. you reference VRAM in your discussion of Tomb Raider benchmarking, yet VRAM does not exist on Apple silicon. So IMO we do not know (or at least I certainly don't) exactly how RAM allocates under gaming on M3 chips. We do know that the same RAM is used for everything, concurrently.
So if I was to make an effort at comparing my point is that I wanted to know what the OP's RAM was because - IMO - RAM is an important parameter to consider in any analysis of M series performance, and I would want to make valid comparisons. Your experience with game demands on VRAM that does not exist in M-series Macs is meaningful (and hella more than mine), but from an experimental standpoint I would not automatically assume that on M3 games will absolutely see no impact from having in excess of 36 GB UMA RAM.
Note that if the OP had responded "I have 128 GB" the point would be moot and I would have no concerns that my 96 RAM might affect comparative results. Also note that I respect your opinion and I expect that it is very likely correct, and that most likely more than 36 GB RAM would not be of value if the game is the only app running.
You have the right to be curious and wanting to do an accurate comparison. Yes, we all know that UMA works differently and the CPU/GPU has access to the whole physical memory. Yes, the RAM size is also an important factor but again it all comes down to what you’re using the computer for, if your specs are enough or if you would benefit from better specs.
VRAM does exist even in UMA and on Apple Silicon, just not as distinct as in the case of dedicated GPUs. According to Apple ”the limit on amount of GPU resources an app can allocate has two values to be aware of. The total amount of GPU resources that can be allocated, and more critically, the amount of memory a single command encoder can reference at any one time.” The ”recommended maximum working set size” command helps you to control how much memory is available/used. Metal is able to allocate more memory beyond this though.

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I’m not familiar with how it’s used exactly, if it’s written in both macOS and applications but Apple states that the GPU working set size for 32 GB is 21 GB. That’s what my screenshot of Tomb Raider shows. With 64 GB you have 48 GB VRAM. So it’s not recommended to exceed these values in order to have a reliable system.
Games are just like other software. The data, pixels, shaders, effects and other stuff are loaded into the memory and displayed. The more memory you have the more data you can have access to without having to write to/read from the disk. That improves the performance. That’s why the highest resolutions like 4K and ultra settings require large VRAM. That’s how it works with UMA on Macs too. The difference is that thanks to UMA you have access to more shared memory and don’t have to swap data between memory and disk as much.
Now when you have a game like Deus Ex that needs about 8-9 GB for max resolution and settings you wouldn’t benefit at all from more free RAM because there’s nothing more to be loaded into the memory. You would absolutely see no impact on the performance from 96 GB. It’s like being hungry and feeling full after a burger. Another table full of pizzas and tacos wouldn’t matter because you’re not hungry anymore. If you find a game that would use 70 GB of RAM you would benefit from 96 GB but the largest GPU VRAM on PC side is 24 GB so that’s the maximum you need for modern games.
In fact the peak VRAM use even with ray tracing at 4K is 13.9 GB in Hogwarts Legacy. Even on PC Deus Ex uses only 5.5 GB VRAM.
Other applications can certainly benefit from large memory. ArtIsRight did a comparison between M2 Ultra with 64 GB and 128 GB. The performance in apps like Lightroom and Photoshop was almost identical. Only when he used a 56 GB file in Photoshop he could see a huge advantage with 128 GB. That’s pretty logical because with 64 GB not much is left for the system to work with.