Overall, I agree, especially the unplugging part. It's just optimizing for time doesn't really apply in my case. I can carve some time in the evening, but if I spent energy at work, I can hardly learn much.
But, some things like doomscrolling and procrastination are both huge energy sinks as well as timesinks. However, targeting them is very hard (again, for me), as it is usually not the root problem but a symptom of anxiety and uncertainty, which I often cannot deal with. If the root of the problem is boredom, it should be much easier to unplug and occupy the brain with something more wholesome.
Another thing is obsessive optimization, "am I studying/practicing the best way possible?". "Is it worth it with so little progress?". I keep falling to such traps. Writing this, I found that I feel that I lack an example of people doing stuff in a suboptimal, slacky, yolo way, deriving fun and still achieving some results in the end.
So probably the thing you need to start practicing and learning is how to deal with anxiety. Conveniently those sessions can fit right into the time slots you're currently spending procrastinating because of selfsame anxiety. See how long you can sit with it and reassure yourself, before reaching for the phone. Once that's been tamed a bit, I think the ability to enjoy doing something poorly will start to appear naturally as a by-product. Or, you can force the issue a bit by adopting a "punk" ethos: "I suck at this, but fuck you, I'm doing it anyway." And there's your example of doing things in a slacky YOLO way too: listen to early punk rock. They did a pretty good job of channeling their anxiety outward into creativity and energy. And there's a "punk" version of almost anything you can think of. Keep it simple, be a beginner, maybe even mock the experts - some of them need it. Good luck.
Yeah I think reaching for the phone can very easily be a soothing mechanism. Like I've noticed sometimes when something a bit socially uncomfortable has happened, like half the people in the room immediately grab their phones. If you pay attention to when people grab their phones, you start to see it a lot.
Though I think that insight is also probably the first step toward working on the issue. The phone habit masks the problem, but when you take the phone away it can also reveal the truth of how bad it's gotten. Like why are you having these anxiety issues? Is it a lack of sleep, too much caffeine, something to see a therapist about, maybe go on meds? Questions worth asking at least. Self-medicating with doom scrolling isn't going to make things better that's for damn sure.