There's the XY problem that should've been mentioned sooner.
Not that it improves the situation much since the killfeed does calls for getting weapon names, assisters and such, but those are things you can recreate.
For Source Scramble, you can allocate a
MemoryBlock (size 0x64 in TF2, not sure about other games), then populate the members then
SDKCall.
This plugin reads / writes offsets in a CTakeDamageInfo struct retrieved via DHooks (I went this route because the extension's objectptr accessors have a few issues), but it should be the same principle with the manually-allocated one.