Hi Darshan,
If you want to stick with the AsOpcUac library, you could use the UaCld_ReadBulk and UaClt_WriteBulk function blocks to read/write multiple nodes at once.
Another option which may be faster is to connect mappView directly to the Lenze PLC without going through the AsOpcUac library first. You can do this by configuring an additional server for mappView. You can then bind to nodes on the B&R PLC as well as nodes on the Lenze PLC. However, keep in mind that you will have to use the correct syntax for the Lenze PLC’s namespace in the bindings. I recommend using UA Expert to troubleshoot this.