Maybe slightly OT, since this concerns AMD older AM4 platform with a Zen3 APU core, but working ECC support looks like this and is definitely present on my system:

    $ sudo ras-mc-ctl --errors | tail -n5
    14 2023-08-20 20:16:41 +0200 error: Corrected error, no action required., CPU 2, bank Unified Memory Controller (bank=17), mcg mcgstatus=0, mci CECC, memory_channel=0,csrow=0, mcgcap=0x0000011c, status=0x9c2040000000011b, addr=0x36e701dc0, misc=0xd01a000101000000, walltime=0x64e31c78, cpuid=0x00a50f00, bank=0x00000011
    15 2023-08-23 17:17:49 +0200 error: Corrected error, no action required., CPU 2, bank Unified Memory Controller (bank=17), mcg mcgstatus=0, mci CECC, memory_channel=0,csrow=0, mcgcap=0x0000011c, status=0x9c2040000000011b, addr=0x36e701dc0, misc=0xd01a000101000000, walltime=0x64ea5188, cpuid=0x00a50f00, bank=0x00000011
    16 2023-09-03 16:52:15 +0200 error: Corrected error, no action required., CPU 2, bank Unified Memory Controller (bank=17), mcg mcgstatus=0, mci CECC, memory_channel=0,csrow=0, mcgcap=0x0000011c, status=0x9c2040000000011b, addr=0x36e701dc0, misc=0xd01a000101000000, walltime=0x64f4d227, cpuid=0x00a50f00, bank=0x00000011
    17 2023-09-15 21:37:59 +0200 error: Corrected error, no action required., CPU 2, bank Unified Memory Controller (bank=17), mcg mcgstatus=0, mci CECC, memory_channel=0,csrow=0, mcgcap=0x0000011c, status=0x9c2040000000011b, addr=0x36e701dc0, misc=0xd01a000101000000, walltime=0x65071ed7, cpuid=0x00a50f00, bank=0x00000011

This is with an ASRock B550M-ITX/ac and a AMD Ryzen 5 PRO 5650G. It used to work the same with a Ryzen 5 3600 (using a dedicated GPU for video output) before I upgraded the CPU.

To detect and log ECC activity on modern GNU/Linux, you will want to have the "rasdaemon" service active. I will decode MCE (and other hardware-related) errors and persist them to the database that is shown being queried above.