Four modules are not ideal in general, see
RAM explained: Why two modules are better than four / single- vs. dual-rank / stability testing
As you can see in
this video from Linus Tech Tips for example, on an X670E Carbon Wifi with a 7950X3D, the 4x 16 GB refusing to run at EXPO speeds is the one thing that did not work properly on that PC. In this
follow-up video, he states again that this was the only mistake that was made, not using 2x 32 GB when you want 64 GB total. And this is totally correct, especially for AM5.
Any total RAM capacity you want, with DDR5, try to reach it with two modules only. First i'd make sure you actually need that much RAM for your workloads, this would only be required for professional workloads. For daily use including gaming, you'd have more than enough RAM if you only use 2x 16 GB in slots A2 and B2, which is the optimal configuration for most people with DDR5. If you do need the full 64 GB, then it's much better to use a kit of 2x 32 GB instead of combining two kits of two to have four modules. Four modules makes everything worse.
Then, another mistake is to use two different models of RAM kits. Even though they might have similar specs, those modules are likely completely different, using different memory ICs (memory chips) for example, this throws off the memory system.. It can pose a considerable challenge for the parameters on the memory bus, which then have to be a compromise, because there can only be one set of parameters for all the installed RAM at once. Sometimes there is no good compromise.
The best way for any modern motherboard is to use a RAM kit of two identical modules, this is equivalent to a racing bike. The second best way is to use four identical modules, this is the equivalent to a van, you should only use it when you can't reach the desired total RAM capacity with two modules. And there you should use a kit of four matched modules, with an EXPO profile if possible.
Of course then the speed might not be this high, but you have to realize, once you simply add two kits of two together, their XMP/EXPO profile goes out the window, since it was only meant for those two modules of one kit, each on their own. When you use four modules, the stress on the memory system doubles, and the electrically it becomes worse. This makes it considerably harder, sometimes impossible, to reach the same speed as with two modules. So it's always best to use a kit of two identical modules only, the second best thing (in a distant second) is to use four identical modules. Four mismatched modules is just asking for trouble.