A Question from a Seeker of Knowledge: How Does Islam View Other Faiths and Internal Differences?

Assalamu alaykum. I'm on my own spiritual journey, having stepped away from Christianity, and now I'm eager to learn about various world religions through theology. I thought starting here would be beneficial. I'm curious about the Islamic perspective on Christianity, Judaism, Druze, Zoroastrianism, and other neighboring beliefs. With billions of people, everyone can understand a scripture differently. So, why do so many conflicts arise over branches and what some call 'heresies'? How do you see the different sects within Islam and other faiths? From what I've seen, Christianity seems more lenient toward diversity. I mean no offense at all-if anything I've said has upset you, please let me know so we can talk about it.