Hello follow the oficial docs here - https://learn.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-sync-configure-filtering#inbound-filtering
There is a logical "AND" between multiple clauses, and a logical "OR" between multiple groups
In this docs - we found this https://learn.microsoft.com/en-us/azure/active-directory/hybrid/concept-azure-ad-connect-sync-declarative-provisioning
STARTSWITH, NOTSTARTSWITH A string compare that evaluates if value is in the beginning of the value in the attribute.
So I recommend you to separate your conditions in groups
Group1 - Name Attribute - STARTSWITH - abc
Group2 - Name Attribute - STARTSWITH - Bu