I am not very proficient in the topic, but I understand your question an I do have a little live-hack - to glue similar tasks. For example, if I need to weld something, I am not going to do this rn but I am going to throw all metals which needs welding into one basket. When lots of weld work has been gathered or when something important needs welding rn, I do all welding at once. That might save some time to assemble and to disassemble my welding workplace.
To me writing is amenable to fragmented time.
When something is kicking around my brain, getting it out on paper takes but a moment.
Fragments of writing from fragmented times.
Immersive reading requires a time chunk.
Writing can coalesce while doing something else.
1. I think consistency is really the key when it come to writing. You’d be surprised how much you can write in 15 minutes per day if you do it every day. The difficult part is doing that 15 minutes, every day, for months.
2. I recommend looking into the work routines of famous writers. There is a good book on the topic called Daily Rituals. Two that I recall were Hemingway, who wrote immediately when he woke up at 5:00, and Kafka, who managed to write after working his mundane office job all day.
3. In terms of learning, I really recommend looking to a SRS program like Anki, combined with list-formatted data on the topic you want to learn about. For example, if you want to learn about the American Revolution, get a PDF of an encyclopedia on the topic, then add one new encyclopedia entry per day. I do this for a variety of topics and find it much more efficient than reading long books. Using a SRS program also is the best way to make your learning time efficient.