Considering Islam After a Long Search: Questions I Still Have

Assalamu alaikum. I come from a North Indian Hindu Brahmin family and spent years exploring different faiths looking for God. I studied Hinduism, Christianity, Judaism, Islam, and religious history. After years of studying Christianity, I became Catholic, but over time I struggled with beliefs like the Trinity, saint veneration, Marian devotion, purgatory, and church authority. Watching debates between Adnan Rashid and James White really opened my eyes. Now I see myself as a Unitarian Christian. I believe in one God and see Jesus as a teacher, Messiah, and guide, but I don't accept the Trinity. So I'm looking more seriously at Islam. The strict monotheism appeals to me, but I have many questions I hope you can help with. Here are my main questions: 1. Why should I become Muslim instead of staying a Unitarian Christian who worships the God of Abraham? 2. Muslims believe the Torah, Psalms, and Gospel were originally from God. If so, why did Muslims stop following the Torah and Psalms? I love the Old Testament, especially Genesis, Exodus, Psalms, Proverbs, and the prophets, so it's hard to set them aside. 3. How do Muslims understand the differences between the Torah and Quran about Ishmael and Isaac? When they seem to contradict, how do you know which is right? 4. How does sin, repentance, and forgiveness work in Islam? Is sincere repentance enough, or is more required? 5. What must a person do to enter Jannah according to Islam? 6. What is Jannah actually like? Is it spiritual, physical, or both? 7. Will I be with my wife and children in Jannah if we are all saved? 8. What about our ancestors? Will we know them in Jannah? 9. My parents are Hindus and have been good, moral people all their lives. How does Islam view the fate of non-Muslims who sincerely followed their religion and never accepted Islam? 10. Finally, what convinced you personally that Islam is true? 11. Can I still read Torah, Psalms, and some Gospels if I become Muslim? I'm asking respectfully and sincerely. I'm not here to argue. I genuinely want to understand why Muslims believe Islam is the final and correct revelation from God, and what would justify converting from my current Unitarian Christian position. JazakAllah khair for reading. Hindu Brahmin with sacred thread, followed Vedic and Hindu faith for a couple years, Christian/Catholic for last 4 years, now Unitarian.