I'll post my own anecdote regarding this topic. Not drawing global conclusions but perhaps providing a different perspective. This will probably be a long read.

I am almost 57. I have two daughters aged turning 25 and 23 this year. Before COVID here were our various diagnoses.
Me: clinical depression, poor impulse control (addiction, in long-term recovery). "High functioning".
Eldest daughter: borderline personality disorder, depression, anxiety, poor impulse control (addiction). Relatively "high functioning".
Youngest daughter: ADD, anxiety, depression. Not "high functioning".
My wife: "doesn't need to see a psychologist".

During COVID, my eldest who had moved out, moved back in with us. Despite the difficulties of COVID, being together probably helped in that we were able to support each other and any deterioration in mental health was moderated. It helps that I totally lifted my game as a practicing stoic during this time and led by example (not bragging, but that's how it played out).

I earn a VERY good living in IT.

I also have a pre-diagnosed heart condition (growing aneurysm on the ascending aorta, not yet at "needs surgery" stage) and hyper-tension. Otherwise in reasonable fitness (another area I lifted my game in during COVID). I'm one of the category of people that lockdowns protected. If I had gotten (or get) COVID, there's a decent chance things won't go too well for me (am fully vaccinated and boosted).

Because I make a good living, I was able to pay for a two week stay in a really good private rehab/mental-health retreat (multi-dimensional professional care) for my eldest - during one of the many lockdowns. We're talking decent 5-figure cost - not covered by our insurance (I should point out that we live in a country with national health insurance, though there's a vast gulf of difference between private and public systems when it comes to mental health). Of all the help she's gotten during the last ten years she's been battling her issues and addictions, it was the single most effective thing she's ever done, to the point that I feel I've gotten her back. She's the best "her" she's ever been. She's now moved out again and living with her boyfriend (a lovely kid, also with pre-COVID mental health issues). They are making a good fist of it, and are both doing really well and feeling very happy despite living largely hand-to-mouth.

I'm about to send my youngest to the same place my eldest went to.

If I had gotten COVID and died, chances are very high that both my daughters would have had worse outcomes. The reality is they wouldn't have been able to afford the help they need. And this is help that they needed before COVID.

I'm not saying that COVID hasn't made it worse. It has. But to those who are looking at some kind of naive calculus as if there's an inverse correlation between "protecting old folks from death" and "protecting young people's mental health" - I say the world isn't that simple.

Listening to my kids and understanding both what makes them happy and hopeful, and depressed and anxious, I'd say that the former is primarily related to connection, love and focusing on what they can control vs what they can't. The latter, seems to a great degree related to focusing on what they can't control - the state of the world, its politics, climate change and "the fact that everything is turning to shit".

This is where I encourage them (by example and through discussion) to adopt stoic philosophy as a way of living and being. It's been what kept me sane during COVID and helps me deal with the shittiness of life while focusing on the beauty that life still holds.

My 2c (probaly $20 going by the length of this post. Apologies).