I am wondering how to pronounce "in that", where in that is a synonym for because. I have little understanding of reduction. Is it right to pronounce it /inə/?
Personally, I would not understand what "/inə/" was supposed to mean. First, I would best understand /ɪ/ as the first syllable, same as "in". At least where I have lived, people would also retain all the consonants.
Overall, if speaking quickly, I would probably say it as /ɪn.ðət/. I'd say it as one word, and with the vowel of "that" reduced to a schwa, but it would still be recognizable as the original words.