Can someone help me make sense of my Mother’s passing, please

Assalamu alaikum. I know I probably shouldn’t be sharing this everywhere but I’m really struggling and I don’t know much about the finer points of Islam, so hearing from others who know would mean a lot. My dear mum passed away a couple of weeks ago in hospital. She was relatively young, in her early 50s - my closest friend and guide. Alhamdulillah she was very devout and always said she was looking forward to meeting Allah swt. About two weeks before she died she started having a pain in her side so I took her to A&E. We thought it might be a gallstone. After scans they found fluid in her abdomen and admitted her. For two weeks she was treated for conditions she didn’t have, and only two days before she passed a biopsy showed she had an aggressive stage 4 sarcoma. She died when her bowels pushed her diaphragm so high she could barely breathe even with maximum oxygen. They had to keep her on morphine and we were told to prepare for her passing. I’m shattered because she had seemed fine before all this. I’m broken because, as her eldest daughter, I spent every day rushing to the hospital from 9am–9pm watching the person I loved most get worse. I begged Allah swt to spare her, to give us more time or good news, but she kept declining. When she had the strength she would recite Quran. I regret that I didn’t have deeper final conversations with her - I was in denial the first week and just focused on caring for her. Alhamdulillah she wasn’t afraid of dying. I just don’t understand why Allah swt took her. Why He took my dad’s soulmate, my little sister’s mother, a sister and friend. I know, subhanAllah, we are not supposed to question Allah’s decree and that this is Qadr, and I tried to find peace with that, but these past few days it’s been really hard. I see her everywhere, I hear her voice, I feel her presence and it’s breaking me. I keep thinking that every day that passes brings me closer to my own end. I can’t fathom why this painful trial came to my family, but I know trials are part of life. Please make dua for her - may Allah grant all our loved ones Jannah. It’s devastating to accept that I won’t wake up and see her again. I lived for her: I studied hard and worked hard for her, I wanted to give her the world, and now I can’t. Was she meant to die? Was this written for her in the Divine Decree? Why would Allah allow her to suffer so much those final weeks - unable to walk, eat, or speak much. She didn’t eat for two weeks before she died and gradually lost feeling in her legs. I can’t understand why this happened to someone who loved Him so much. Could it have been because she didn’t look after her health or because the stress at home worsened her condition? After my sister-in-law moved in, her stress increased and I noticed her energy and appetite decline. Is it possible stress triggered or sped up the illness? Did Allah plan this because of her choices? I’m struggling to find peace because I don’t understand. Please keep her in your duas. Any thoughts from those who understand more about faith, death, and patience in Islam would be so appreciated.