So you found a solution. What don’t you like in this solution?
And your solutio looks good to me: It’s better to sort on the final block. Sorting in a var block is probably not the best approach: you noticed that you can group vars like in uid (var1, var2) for example. So the sort might not be reused as you think.
Please log a Bug Report for the query returning an error ( I don’t see an obvious error but the query is complex, it deserves more attention through an Issue in Github imo).