The message that is returned is not accurate as it is referring to the name that it will give the network name resource (SQLPROD_AG_SQLPROD), and it is labelled incorrectly as the DNS name. You can see that the network name resource in your AG is named SQLPROD_AG_SQLPROD, and that is what it's referring to.
It really should say something like, "The ...
If (and that's a big IF) you're running SQL Server 2019 (CTP 2.4) then you can get the last known ACTUAL execution plan for a previously cached query plan:
FROM sys.dm_exec_procedure_stats AS ps
CROSS APPLY sys.dm_exec_query_plan_stats(deps.plan_handle) AS qps
WHERE ps.object_id = OBJECT_ID('dbo.spMyProcedure');
It looks like the other suggestions so far all lead back to sys.dm_db_index_physical_stats
This is where you will have to look to get the index stats, but you could look to use the LIMITED option and restrict it to specific indexes at a time.
With the size of your table, I would want to know how quickly fragmentation occurs to help me confirm that the ...