Would appreciate some thoughtful answers, assalamu alaikum

Assalamu alaikum - I’ve been carrying a lot of questions and would be grateful for sincere, simple answers. 1) If Allah already knows everything, why does He test us? What purpose do tests serve when the outcome is already known? I’m trying to understand how tests fit with Allah’s foreknowledge. 2) Allah is described as Ar-Rahman and Ar-Raheem, so why does His mercy and forgiveness seem to be promised to believers? For example, there are verses about the disbelievers’ punishment. How do we reconcile the attributes of vast mercy with descriptions of punishment for those who reject the truth? 3) If guidance ultimately comes from Allah, how are people who never received that guidance held responsible for disbelief? Many are born into a culture or religion and rarely seek alternatives. The Qur’an says Allah guides whom He wills - so how is it fair that some people never become Muslim? 4) The story of Iblees (Satan) involves a challenge and a promise to mislead some people. Why would Allah allow that challenge to take place? It seems hard to understand why an all-powerful, all-good Lord would permit such a test. Also, if Allah can make everyone guided, why not simply make all people believers? 5) The story of Nuh (Noah) raises practical questions: a worldwide flood mixing fresh and salt water would harm marine life, how would animals survive on one ship, and how to explain distribution of species like marsupials in Australia? I know some details may be interpreted allegorically, but I’m unsure how to reconcile the narrative with these practical issues. 6) I’ve seen an argument about the inheritance verses (An‑Nisa 4:11–12) claiming the prescribed shares can produce a situation that seems mathematically impossible to divide straightforwardly when certain heirs are present. Different schools and sects disagree on interpretation, which makes it feel unclear. How do scholars resolve this without it looking like a serious error? 7) I accept that life is a test, but how do we make sense of truly horrific suffering as part of a test - for example, a child being abused? It’s hard to see how such evil fits into a merciful divine plan. These doubts are weighing on me and making me feel distant from the deen. I don’t mean to be disrespectful - I’m honestly confused and want to understand. I’d appreciate compassionate, straightforward answers, references to tafsir or scholars if possible, and any personal reflections that helped you come to terms with these questions.