MENJAWAB PERTANYAAN - English

ummmm, no.

The verb form given by Mxmachine is directly related to the grammar and consequently meaning - essentially why two ”had”s occur in sequence. It’s described as past perfect both in American English:

https://learningenglish.voanews.com/a/past-unreal-conditionals/3181755.html

and British English:

https://dictionary.cambridge.org/grammar/british-grammar/wish

”I only wish” is indeed an expression that there is regret that what had been wanted hasn’t happened.

”had had” is the past perfect form, as well as that for the past subjunctive perfect, as you had pointed out.

Past subjunctive merely expresses the idea that the wish existed in the past. Past subjective perfect tells us that a wish/request existed in ”past in the past”, i.e., at a past point relative to a point in the past.

Perfect tenses such as present perfect are all about relevance of something from the past to the present point in time while past perfect describes the relevance of something to a point in the past of something further in the past.

A regret/disappointment is not just something relevant to the present point of time but also a range of points in time up to the present time frame. Hence past perfect is logically the correct verb form descriptor here. I suspect that the grammar experts at Cambridge University and VOA (who incidentally have quite a good English course if American English is your thing) also agree with my opinion...

Any good English grammar book - British or American - will have ”wish + past perfect = regret/disappointment” as the correct grammatical form. Simple logic...

As for unreal conditionals using a past perfect syntax, as to whether it would be labelled ”past perfect” or ”past subjunctive perfect” - that would depend on whether it is being reported as a fact relative to a point in the past or whether there is a relevance of that event happening ”past in the past” to some point in the past.