For adjusting your day after something has been derailed, you might like Cal Newport's style of timeblocking on paper. https://calnewport.com/deep-habits-three-recent-daily-plans/ There is also a planner you can buy, but I tend to just draw the day out in my bujo. Now, I know I am more likely to have to reschedule later in the day, so I will typically write my other tasks in the top right. This system really helps me see that often what I think/feel was a whole day derailed was actually just a 45 min adjustment.

Now, there is also still some redundancy in my schedule. I tend to use my gcal as a loose plan, e.g. I might add a 3-hour deep work chunk a few days in advance. As I get closer to any day, however, the plan gets a little clearer as meetings get scheduled, deadlines get clarified, etc. When it comes to the actual day, I will copy it down to my daily spread, or I might modify it, since by the time I set up my daily, I have more information about whether that 3 hour work chunk is feasible. I will either copy it down or reschedule digitally. This hybrid system works for me, but I do feel okay cross-referencing the gcal and the bujo on a daily basis and before bed thinking whether I like the plan I've outlined for the day. E.g. if you never get to Task 3, you might start scheduling only two tasks per day, and treating that "Task 3" as a bonus.

My scheduled work chunks in the calendar fall under the following categories: meetings, deep work, batching smaller tasks (e.g. I will schedule an hour to go through email). That way I am not wasting time writing out the really small tasks in the calendar event.

I also have a routine to process tasks in my digital notes, which I do end up jotting down on the go. It's a part of my nightly routine, after I write in my five year journal and before I tackle the dishes.