You can take advantage of reading whole structs in OPC UA servers as of Ignition 7.9.12 and 8.0.0.
When you bring the tag in you’ll notice Ignition presents a JSON value. The strategy here is a little involved but it works.
For each of the UDTs you’ll be subscribing to in the PLC you make a corresponding UDT in Ignition. It should have a “Source” OPC tag member that will correspond to the Node with the struct value in the server and as a result have a JSON value in Ignition. Then for each member of the UDT you have a Derived Tag member that references the “Source” tag using the jsonGet and jsonSet expression functions to get/set the member value out of the JSON value.