I asked a Dev this question from our integrations team and this was their response:
We support Security Lake for Guard Duty, CloudTrail, VPC Flows, and Route53. And other providers pushing into Security Lake would require a DSM update to add parsing and mapping for events. There is no "Generic OCSF" parser yet. QRadar can parse metadata generically, but the EventID could be in various places depending on how a vendor chooses to slot things into the schema.
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Jonathan Pechta
IBM Security - Community of Practice Lead
jonathan.pechta1@ibm.com------------------------------