Wouldn't it be worth a try to use AMDP instad of ADBC, i.e. encapsulating the call of the native stored procedure inside an AMDP method? Syntax of the native SQL statements is checked better there.
See Calling an SQLScript Procedure from AMDP or SAP HANA, Call Database Procedure.
See also SAP HANA, from ADBC to AMDP.