I'm not an expert on theology but I've heard that Christianity is filled with inconsistencies and incongruencies. My question, if this is the case, is whether this is normal for the major theologies or it is a specific fault of Christianity.
On religious views inconsistency is not necessarily a fault, after all God is supposed to surpass human reason and logic. And many paradoxical notions come from general monotheistic doctrines, like creation from nothing, omnipotence, omnibenevolence and omniscience, that Christianity and Islam share. Buddhism is different, although some versions of it can be interpreted as mystical monotheism along panentheist lines.
We should note that there is no such thing as a monolith Christian theology, there are Catholic, Orthodox, and Protestant denominations, not to mention lesser ones, with multiple theological systems and philosophical interpretations each. On philosophical issues for Christianity specifically see Philosophy and Christian Theology. The official philosophy/theology of the Catholic Church, Thomism, is considered quite rational and coherent as these things go, even rationalistic. There is the opposite extreme too, called fideism, best known from Tertullian's anti-rationalist motto concerning articles of faith:"It is to be believed, because it is absurd… it is certain, because it is impossible". Islam also has rationalistic (Kalam), mystical (Sufism) and fanatical (Wahhabism) versions. A version of rationalistic Islamic theology, Averroism, was one of chief influences on Thomism.
Christs teachings were not written down until some time after his death. Given the nature of that, his authority couldn't weigh in on the composition and editing of these. It took some 300 years to settle on the New Testament canon, and the final set is very open to dispute, especially inclusion of The Book of Revelation. There are big divergences between Eastern Orthodox interpretations based on original Greek writings, and Catholic iterpretations based on sometimes bad translations into Latin https://en.m.wikipedia.org/wiki/Theological_differences_between_the_Catholic_Church_and_the_Eastern_Orthodox_Church
Very little Christian practice or theology is based on the words and teachings of Christ, but instead the disciples and later community (eg. hell, non biblical,from Norse word). The idea of 'progressive revelation' is essential for this, but poses it's own problems. Reform has happened by various council's, and after the division of the churches by different means within each, such as papal bulls. There is no definitive version of the new testament. It is not considered revealed directly from god, although the apostles experienced pentacost. Some Christian patriarchs have been considered to have final authority of interpretations.
This should most directly be contrasted with Judaism, where interpretation is 'argued out' in rabbinic study, and the body of believers to some extent have sovereignty, even occassionally arguing with the deity. The core religious text is a single definitive one, considered to be the revealed word of god, though there are layers of interpretation open to different degrees of questioning.
Mohammed was able to write his teachings down himself, revealed directly from god, so they are seen in Islam as unchallangeable (with the exception arguably of the gharaniq verses). They have final authority. But schools of jurisprudence have developed profoundly different interpretations.
The core text of Buddhism the Tripitaka was composed by the early community based on sermons of the Buddha, and transmitted orally at first, like the Christian template - the worlds first type-printed book was a Buddhist text, but still over 1,000 years after Buddha. In the Therevada school, around 1/3 of Buddhists, focused on Sri Lanka, this is considered the definitive text, the Pali Canon. In the Mahayana school, focused in China & Tibet, it is authoratative, but other sutras are also revered, often more; and there isn't a clear definitive canon in any of the sub-schools. The Tripitaka is not directly revealed words, but guidance and discussion by a highly developed being (not technically a deity, though he preached to deities including the creator, Brahma). The key divisions are among schools of philosophy within Buddhism. There are substantial disputes between schools over which others have any validity or deserve any respect. There are high degrees of synchretism across the Buddhist world, especially given wedding and funeral rights are not found in the sutras.
Texts, what authority they are considered to have, and the process of authoratative interpretation of them, are crucial to understanding different religions. In Christianity, the discovery of the Dead Sea Scrolls, the earliest written versions of many books of the old testament, and mainly contemporary to Jesus, pose various problems for modern Christianity. I really like the book by Barbara Thiering on this, Jesus The Man https://www.goodreads.com/book/show/296402.Jesus_the_Man There are big problems reconciling biblical records of events with Roman records, and this book does a lot to reconcile this, and to explain the doctrinal position against previous religious practices that have been recorded as miracles. Resolving these comes at significant cost to modern religious practices.
The consistency of the bible has implications for all the Abrahamic faiths. It's a big topic https://en.m.wikipedia.org/wiki/Internal_consistency_of_the_Bible
Many of the theological disputes or contradictions (eg. Problem of Evil, & theodicies against it) arise out of textual issues.