Hi Roger.
At this point, do not do a single thing. You’re good-overkill on ram capacity, if anything. It makes little to no difference between DDR 4 or DDR 5 in MSFS, based on the specs you have provided, for the same generation of CPU. The Alder Lake platform supports both, depending on the MB you are using. If you are on a Z690 MB, you are already using DDR5.
On the other hand, if you are using a board which supports DDR4 only, the answer is the same. Synthetic benchmarks may tell a different tale, but for MSFS exclusively, you will see diminishing returns by upgrading to a board that supports DDR 5. The cost and effort is simply not worth it, unless you have money to burn, and absolutely want the latest and greatest.
Also someone mentioned “more ram more lag”. This is not entirely true. Yes it can incur a slight latency penalty, IF you are overclocking your RAM past it’s XMP profiles, or trying to push you CPU past 5.1-5.2Ghz on more that 2 power cores. This is because the memory controller resides in the actual CPU.
The takeaway here, is if you are trying to push your hardware further up the frequency scale, as far as it will allow you, (and that is not by much on Alder Lake) simply remove two sticks of RAM from each channel. Which again since you are in excess of, won’t cost you a dime.