Syntax for openquery for oracle linked server with an merge into using update statement

I have an ORACLE Update Statement which I want to run on sql server as a step in a scheduled job. The ORACLE Update Statement, as it can be executed on sqldeveloper e.g., reads as follows:

merge into TABLEA A
using
(
select

from TABLEB B
..)
when matched then
update set A.X = B.Y

As you can see this is a ORACLE merge into statement.
I have searched this forum and other sites, but couldn’t find what the syntax is
when using SQL server openquery. When I write the statement like:

update
openquery
(linkedserver,
‘oracle sql statement as above’)
I get an error saying Incorrect syntax near ‘)’.
The SQL Server Version is 15.0 on Windows Server 2019 and the ORACLE DB is Version 19c.
Thanks for any hint on this issue.