The process is a bit different depending on the medium.
I do mostly read books on electronic format, so I can highlight and sync cross-device the parts I find most interesting, sometimes with different colours depending on how much the message resonates with me.
After I read a couple of chapters or by the end of the book – right when recalling is most effective – is when I transcribe those highlights down to notes. When transcribing, I do split my screen in two; I open the book with the highlights synced on one side, and the text editor on the other side, so I can transcribe while scanning for highlights. I do not copy and paste the highlights from the book – sometimes this is not even allowed by the reading app because of DRM – I do type every highlight by hand; otherwise there would be no point. I do this for learning and retaining knowledge. Summaries are a side-effect of the process, not the goal.
I experimented with a few e-ink readers, specially for technical books I found the of iPad mini and the MacBook Pro the perfect match. With Apple devices, I often use the Apple store to buy books and the Books app for reading them, it syncs my ebooks beautifully across multiple devices. Lately I found the Amazon store and Kindle app quite interesting as it allows me to later on sync with Linux devices too.
For writing down the notes, I do usually use VSCode with Markdown TOC extension.
Once I have the notes, the idea is to iterate and refine them on successive reading waves, reinforcing the learning.
Articles are usually way shorter than books, as they are web-based is kind of difficult to highlight them right away. So I tend to take notes at the same time I read them or after a first reading pass. I do split the screen with the browser on one side and the text editor on the other. Typing every word by hand as a way of reinforcing the message. Once I finish I tend to do a final recap on the entire thing.
For talks and presentations I have to stop the viewing to write down what I've just seen. I do often watch videos at a greater speed, usually at 1.25x or 1.5x depending on the vocalisation of the speaker or the difficulty of the topic. Doing so usually compensates the pauses.
Taking notes slows down quite a lot the amount of stuff I can ingest, but I found out it really helps me retain knowledge in the long-term. It allows me to come back, review and even share concepts that could be long forgotten otherwise, the slow intake trade-off is compensated.
If you found a more optimal way of doing this, I'd really appreciate hearing about it.