According to your Motherboard's QVL List for the 5000G/GE processor for RAM MEMORY your motherboard supports 4000Mhz:
Its SPD Speed is 2400Mhz so something is differently wrong.
Looking at your MSI Motherboard's Spec for RAM MEMORY to get 4000Mhz you need to do the following under A-XMP OC:
I am not familiar with MSI BIOS A-XMP Settings but it seems you need to set A-XMP to 2DPC-1R to get 4000Mhz from your RAM Memory.
If you have done this already then I suggest you open a MSI Support ticket and see if your Motherboard needs to be RMAed and checked if it is defective since you do have compatible RAM installed from the QVL List.
A-XMP automatically over-clocks the RAM Memory safely. Just need to enable to correct RAM Profile.
I don't overclock anything unless I know exactly what I am doing since you can damage the hardware being Overclocked. But like you I also manually overclocked my RAM from SPD speed to the speed rated by the RAM I have, 3600Mhz.
In my case I just needed to change a couple BIOS Settings to accomplish it. In my Asus Motherboard BIOS I can choose various speeds for RAM memory. So I selected 3600Mhz and then under FCLK which is 50% slower than the RAM Speed I inputted 1800Mhz. I have had no issues so far.
Asus has something similar to A-XMP which is called DOCP. But many Users were having issues using DOCP including myself thus I manually overclocked my Ram.
If for some reason you input incorrect data when Overclocking, BIOS will generally catch it and revert to the SPD speed automatically until you input the correct parameters for Overclocking the RAM. But still you can still input incorrect parameters but not enough for BIOS to reject it but then you will have all types of RAM issues when you boot into Windows.
Just for your information to get the best performance out of the 3000 Series Ryzen processors (Sweet Spot) the best speed is 3600Mhz with FCLK at 1800Mhz.
The best Sweet Spot for the Ryzen 2000 series processors is 3200Mhn with a FCLK of 1600Mhz for the best performance.
But according to PC Magazine article the Sweet Spot for the 5000 Series Processors is 4000Mhz: https://www.pcgamer.com/amd-ryzen-5000-cpus-may-run-best-with-faster-ddr4-4000-memory/
You can download a RAM MEMORY Program that gives you all the Data to input for various RAM Speeds to overclock the Memory.
It is called Thaiphoon RAM Tool.
By the way, Good luck in reaching 4000Mhz which will give your 5000 Series processors the best performance.
Also this is the reason for Forums when Users to can help other Users with their problems.
You are right about the A-XMP -- I enabled that and it should have set up a "safe" maximum clock profile. Indeed, it set up 4000MHz -- then, crash & burn. Per your idea, I will try and play with the FCLK setting since I did notice that option in the MSI BIOS. What can go wrong?
Thank you for the RAM program suggestion - I'll mess with that one and see what trouble I can get myself into.
I saw the same pc mag article (among others) which was why I went with the 4000MHz ram -- hence, my annoyance -- sigh!
U R Da' Best!