Can't think of what to do, hence scrolling

Try reframing how you think of these things slightly. Watch https://monotropism.org/wp-content/uploads/2022/05/Monotropism-animation.mp4 and just believe your brain works like that for argument sake. I know it's tough, especially because the act of telling you to do anything most likely will lead you to not wanting to do it, a frustrating trait of this brain.

Stop worrying about how normal people do things and try better to understand how your brain does things. Reframe how you see the problem as something where you're trying to get fixed to be normal, and accept that's not possible. Psychology's best therapies offer drugs that help you put on a facade of normal, or worse, crank your apathy up to where you just don't give a shit any more.

Have you ever done anything that you were so into, that you skipped meals, bathroom breaks, and other biological needs? Like, to the point of deep hunger, dehydration, nearly peeing yourself? "Normal" brains never do that, or even moderate versions of that. Like, there's a category of self improvement literature that sells the idea of a flow state, because most people want that state of mind and will never obtain it. It's simply something people observed successful people with monotropic brains doing, and made up into a new pop-psych thing to sell.

Spend time actively, consciously noticing what hooks you. Aggressively give up on those things that don't. You may habitually spend time doing things that you don't actually like, but you are unconsciously forcing yourself to keep doing. Step out of your comfort zone and try a new thing, activity, genre, media, person, sexuality, etc. Most people spend their whole life being forced into a mold, and that mold is almost certainly not compatible with the needs of a neurodivergent brain.

Structure is NOT a requirement, and for me, personally, isn't compatible with anything that makes me happy. Still, my entire upbringing continuously shoved structure down my throat. School constantly reinforced that I needed to organize my binder, write in a planner, and multiple times I remember being assigned projects like setting an itinerary for a vacation. I hated it, felt unnatural, stressful, and I never managed to adopt the habits they were forcing on me, yet still managed to be a successful person. I could have self-loathed about it, but instead I managed to kick the bs and move on. When I eventually got married and started going on vacations, my wife (who has an ADHD diagnosis, though wasn't diagnosed until after this story) planned a very structured itinerary for a 2 week vacation in the UK. The trip was stressful to plan, and our daily activities were on a tight schedule, leaving no room to linger where we wanted. While we had a good time, we both look back at random moments off the itinerary as the best ones, and have high regret for being forced to stay longer in some places, and not long enough in others. This same thing happened again on another vacation, we simply weren't self aware enough to avoid it, or were too concerned about following a script of how to do a vacation. Finally, on our third vacation, we approached it very differently. The only preplanned/prebooked moment was what city we were arriving in and the one night stay there, the rest of the two weeks were vague possibilities at best. It was our best vacation, and it's not even close, zero regrets, and that's including a medical disaster. Sorry for the long story, but I feel like it was worth telling you.

I don't fully subscribe to monotropism, even wholly rejected it prior to some of my own realizations. Like, it isn't the final and complete explanation, but it's a much better starting point than everything else out there.

As far as scrolling, it's a tough thing. If you are feeling fulfilled when doing it, stop kicking yourself for it, and instead look to optimize the activity. For example, cut out content that you know you don't enjoy. If instead it's just something you're doing to pass the time, with no real enjoyment, you should probably figure out a strategy to cut it back or out entirely. When brains like ours are bored, the compulsion to fix it is very strong, and will likely drive you quickly to something you will actually find fulfilling if you let it. If you're really lucky, an activity you find fulfilling will be neurotypically amicable, and maybe even profitable, but you should not expect that. Don't try to have multiple things at once, it's not that you can't, it's that you will likely be happier sticking to one thing you enjoy until you don't anymore, and then throwing yourself into the next thing. And try not to kick yourself too hard if/when that happens, sticking with something you don't want to, or putting yourself down for it is antithetical to loving yourself. With this brain, it's not about the destination, it's the journey, and as soon as you do get to the destination you will find an emptiness that can only be filled by starting a new journey.

Happy to chat more deeply about this stuff, feels like there's always more to say. Not sure how well it works with lemmy, but if you check my comments I recently wrote a response to someone in an ADHD community asking about watching movies that feels very similar to this question.