Im 18 and had a similar teenage experience, and I don't have anyone to blame other than myself. I know my pre secondary school life was good, but that was <11, so I don't remember much. I had the ages of 12-14 fucked by the lockdowns, I did nothing but rot in bed and watch youtube between 14-16, and from 16-18 I had my exam years and spent my free time watching jewtube. Now that I'm at uni away from home I wish I had spent my time better. I could have been spending more time with my family, I could have been doing some sort of hobby, and instead I spent my time online. I've been depressed from ~15 until I guess about a year or two ago? It would get to the point of suicidal ideation in the winter, but I never attentionfag self harmed and I toughed it out until spring came. I can't give any advice on getting rid of it, I guess I just lied to myself and gave myself a stronger ego and maybe just got bored of being a miserable fuck. Socialising more helped, and also making an effort to go outside if I felt miserable. Staying at home or in front of a computer is terrible for your mental health.
I don't remember much at all from late 2019 - 2024. My secondary school life was from autumn 2019 - spring 2026 and I don't remember much other than the last 2 years when I moved on to 6th form and socialised a bit more and did some shit. Some of my friends would bring up something that happened in the Covid years and I would normally blank, I only remember vague details.