Entity Framework Core - Take(1), Single(), First()... Not Working with Oracle Provider (ORA-00933: SQL command not properly ended)
Apparently you are targeting an older Oracle database which doesn't support the newer FETCH FIRST N ROWS ONLY SQL construct.
In order to get the older ROWNUM based SQL translation, you should utilize the optional Action<OracleDbContextOptionsBuilder> oracleOptionsAction parameter of UseOracle method and UseOracleSQLCompatibility extension method with value "11" (the only currently supported values are "11" and "12"):
.UseOracle(connection_string, options => options .UseOracleSQLCompatibility("11"))