Correct grammar / style for segments that share the same (lengthy) prepositional object

Question

I'm having trouble with a sentence that uses two (or more) prepositional phrases, which share the same prepositional object. For example, I would like to turn these two statements:

A main theme in this thesis is the proper use of X in Y.
Another main theme in this thesis is the safety profile of Y.

into:

The two main themes in this thesis are the proper use of X in, and the safety profile of, Y.

The above format is based on advice found online HERE (relevant section reproduced below):

Segments that share the same prepositional object

Use commas to separate off sentence segments that share the same prepositional object.
E.g. ‘She flew over, and he sailed under, the Wordsmith Bridge.’

_{Choosing Your Mark, p. 25 (15)
Style Manual p. 82 (6.60)}

However, while I find that this approach works with their sentence, I find that (subjectively) my example above is much less aesthetically pleasing.

At the risk of sounding like I'm asking for opinions rather than confirming / exploring suitable grammar options, is this the right / only way to do this, and if not what are appropriate alternatives?

For instance, are m-dashes / 'interruption' n-dashes allowed / preferred / recommended? E.g.

The two main themes in this thesis are the proper use of X in --- and the safety profile of --- Y.
The two main themes in this thesis are the proper use of X in--, and the safety profile of, Y.

---

_{PS: Note that while the 'comma' and 'n-dash' methods would allow for more than two segments, the 'm-dash' method does not, but this is not a problem for me in this particular instance. But please share your thoughts either way.
Edit: -> PS2: In response to Edwin's excellent comments, I'm reluctant to duplicate Y in that sentence because in my case it corresponds to a very lengthy object which would result in a very bad sentence. (Title edited appropriately to reflect this).}

Answer 1

Not sure why no-one wanted to attempt an answer outside the comment section, but I suppose I should answer this question myself based on the discussion in the comments for the benefit of future googlers.

As per Greg's comment, the constructions concerned are RNR (Right Node Raising) constructions. More importantly, they are RNR constructs applied to prepositional objects.

I have found an old paper called Right Node Raising and Preposition Stranding (alas, paywalled), which seems to use the comma syntax consistently, so I would consider this as evidence that this is indeed the grammatically correct way to express this construct in writing, particularly in the context where the prepositional objects involved are lenghty in nature.