Two things op, other parents often paint reality with rose tinged glasses. I remember finding out that all those new mummies who told me feeding was a breeze and their babies slept fessing up to the reality when we met again in the school playground three/four years later.
Also, teenage years are hard. Home is often their safe space to be vile. Mine were awful.
DS was a party boy and from 16-22ish never felt he should tell me where he was going or come home when expected. There was row after row. He was also obstructive, unhelpful and argumentative. He often implied we were shit, awful parents who didn't understand his generation (remember that - we just didn't express it, we wouldn't have dared).
DD became ill at 15, eating, anxiety, cutting, depression. There was little help available and it took everything I had in me to keep her going at school, to engage with a private psychiatrist and therapists, etc. At 17 she was diagnosed with ADHD. We never recognised the signs but once we knew it all made sense. From that point her recovery started.
They are 26 and 30 now. Graduated with firsts and both have good jobs. DS is married and dd is partnered. They began the journey back to their old, selves at about 22.
You haven't failed. You met an obstacle and have to navigate it. Fucking hard at the time though. All you can do at this stage is love them, feed them, stick to routines and be there.