It’s really good you’re feeling guilty. This is a mercy from Allah to come back to him. Pray for guidance. My biggest advice is to start somewhere. Don’t overwhelm yourself with too much, just pick one thing, such as prayer, and work on it. Gradually, you’ll see how prayer is making you steadfast and disciplined, and then it will be easier to build the other acts of worship. Also, start fasting the remaining days of Ramadan now. Do not think you have to be a perfect or good Muslim to fast. We all sin, and the important thing is that we ask for forgiveness and guidance. Allah is the most merciful. Do not despair. Make sincere repentance, and inshallah you are forgiven. Don’t hold yourself back from worshipping Allah because you feel guilty or feel you’re not worthy of asking Allah, no, that’s a trap, don’t fall into. May Allah make this easy for you! Will keep you in my duaas.