Putting two of the same words together in a sentence has always bothered me

Why is there nothing wrong with this sentence where the preposition for is doubled in the sentence?

Little does she know that this chance meeting with the gentleman with the alluring green eyes sends her life into a whirlwind of events which she had been praying for for a long time.

While it may seem like 'for' is being doubled on its own, what we actually have is two different semantic units, both of which contain 'for,' but which operate independently:

In the first instance, the phrasal verb 'to pray for' is used.

to wish for fervently, to hope. OED 1 a

This contains the preposition 'for,' but 'for' is inseperable, since the meaning of the verb 'to pray' OED 1 b is different from the verb 'to pray for.' Confusingly, in English, they are constructed from and appear under the same lemma.

In the second instance, 'for' is a preposition of duration, 'for a long time' OED A X 27

Neither is redundant to the other, and neither can be cut without changing the meaning of the sentence. (That said, the sentence could bear some rewriting for a number of stylistic reasons, not just to avoid doubling 'for.')