I have never been able to learn very well or a lot of the time at all by bottom up learning, at least at first.
This is a large part of why I never got much at all out of lectures, classes, courses etc. Both at school and more corporate training stuff.
A lot of this is probably related to ADHD and weird brain.
The way I learn things at first is that I need to have a thing I am going to use it for before it is even worth it for me to do more than get an idea about what the thing is about. When I have a thing I’m going to use it for, I just have to learn enough to accomplish what I need to do well. And repeat this process until I feel like my water is above the water, and I have control of it.
For programming this usually means that I can write code without constantly looking up things.
At this point is when I gradually start to learn more and more topics related to it bottoms up. It is usually triggered by me feeling that I’m at a place where it would be useful to understand something completely.
If I start with bottoms-up style learning I may as well not do it, because none of it will stick. But I get a lot out of it when I have a lot of things to tie it to.