@Ano Acco Thank you for reaching out to us, researched on your ask where you want to send all of the Unified Audit Log from M365 Tenant A to log analytics for storage, alerts, etc in Tenant B.
Similar requirement has been discussed over here - https://techcommunity.microsoft.com/t5/microsoft-sentinel/sending-logs-from-one-tenant-to-a-different-tenant-sentinel/m-p/2185531 where recommended approach is to use Azure functions.
However will also check with my team on the same and keep you posted once i have the response.
Let me know if you have any further questions, feel free to post back.