relearning my faith, one step at a time - assalamualaikum

assalamualaikum everyone, i'm sorry for my lack of knowledge and for the long post, but if you have 10–15 minutes i'd really appreciate some guidance from my fellow Muslims. i'm a young adult living in a western country trying to find peace and answers as life changes. i grew up in a shia muslim family but never had real guidance or tools to learn about my deen. maybe i wasn't drawn to it before, or my surroundings shaped my views. it's taken years, changes in habits, and different relationships to reach where i am now. recently i've been dealing with anxiety and depression, and i've been fixating on death and the passing of time. one day things shifted - i began to put pieces together and realised death isn't the end. i looked into the afterlife to comfort myself, and subhanallah it moved me so much. i cried thinking we might get to reunite with loved ones and live eternally. now i'm in this odd spot: i feel pulled to relearn islam while also struggling mentally. i've never connected deeply with my faith, maybe because i didn't understand its importance or the language of the texts. i'm unsure whether this is an awakening or if i'm fearing consequences because of past mistakes. i don't doubt that islam is true or that there's a Creator. i see signs everywhere - the chair i'm sitting on made from materials given by Allah, my body functioning, healing that ultimately comes from Him. i believe in God. my heart and mind urge me to turn back, repent, seek forgiveness, and live righteously, but i don't know what that really looks like in practice. my mental health and numbness make it hard to be sincere and to feel real remorse. what is sincerity in tawbah? what if i've buried my sins so deep that thinking about them causes discomfort instead of true regret? i try to reflect but can't always grasp the significance. is my heart hardened? how do i soften it - does that take time? should i learn about the effects and consequences of sins? and if i fear punishment, does that make my repentance less sincere because i'm acting out of fear for myself? i also have questions about shia and sunni differences. do we get judged differently because of our school? why is there sometimes hostility between sunni and shia communities? what essential knowledge should i learn as a shia muslim? if i stick to the basic pillars and try to live well but haven't studied all the sect-specific things, am i at risk of punishment? i'd be very grateful for advice on how to relearn islam without getting overwhelmed by how much there seems to be to know and do. practical steps, simple resources, or personal tips on softening the heart, sincere repentance, and building consistent worship would mean a lot. jazakallah khair. may Allah guide us all, forgive us, and grant us good deeds that lead to jannah.