Being Online Causes Digital Self-Harm

A few thoughts on this:
Your point is well taken that the internet is an attention-based economy that has evolved over time to capture more and more of this scarce and precious commodity.
That being said, I do believe that there are ways of being online that adds more value to our lives than is taken away. A few of the ideas that come to mind:
1. Being purposeful
Is being online a way to learn, get something done, connect, or solve a problem? Or, is it a compulsive activity you're using to "kill time" or distract yourself. Purpose is important while being online. The online environment is most harmful when we allow algorithms and ads to seize our attention.
Attention is the lifeblood of mental health and it can be a fragile thing. However, when attention is used to enhance our life and experience, in ways other than passive, dissociative losing of self, the resources of in the online sphere can be a bottomless source of nourishment.
2. Connecting with others:
Writing this during a pandemic, it's become so clear to me the difference between talking at one another and talking to one another. For decades we've been saying that the internet is a way of bringing people from all walks of life in all parts of the world together. This is factually true, but it does not necessarily mean that we receive the benefits of social interaction and intimacy through all interactive online activity.
After many Zoom meetups and conducting online therapy, I absolutely believe that people can profit from online interaction. However, genuine, attentive, and spontaneous interaction must be present. Passively swiping and liking--or even posting something flaccidly "to the world" is not the same as connecting to others online.
Look at one another. Say things that are in your heart. Learn about others' lives. Laugh and cry together. All of these will build you up, not tear you down.
3. Active learning:
This is one of the quickest acting and most rewarding applications of positive online activity. The internet can empower us by helping use learn enlivening information or teaching us skills we might have otherwise had to outsource.
Every time you go online seeking an answer or a practical skill, you maintain focus on getting to the bottom of the issue, and you find the answer you need, you are building up a sense of self-efficacy. Learning something meaningful or useful is always self-affirming, and I don't believe doing so online is any more toxic than attending a lecture or reading a paper book.
4. Writing:
Writing is not only a creative process that has the potential for touching others and creating value in the world, it's also a way we learn about ourselves, the world, and affirm our identities. When you write out of interest, desire, connection, and/or pursuit of learning, you're building resilience at a faster rate than being online can harm you.
I don't consider this to be an exhaustive list, but rather just a few of the ways I think we can have a healthy relationship with our online presence. In short, the internet is a powerful tool that also has the potential to do harm, whether by creating dependency or by exploiting our psychological vulnerabilities; nevertheless, tools have their applications and can be a part of an affirming, creative, and productive journey when purposefully used.
I hope this reply is taken in the spirit of collaborative discussion and as a meaningful step towards understanding and synthesis.