Check Out this: https://hackernoon.com/how-css-grid-beats-bootstrap-85d5881cf163 Personally, I'll use the CSS grid or Flexbox over bootstrap. No Container, No extra div's makes HTML code clear to read and No 12 column layout limit which is in bootstrap.

Hey!! I will not say that data structure and algorithm are not important but you don't need to master it at once, This does take time to learn at least in my Experience. And you don't need to learn Every Data Structures there is!! learn the basic array, object, linked-list and most other DS based on these DS only.

I don't know much about Native App, but since you are using Angular have you consider NativeScript.

for basic to advanced you check this course: https://www.udemy.com/the-complete-javascript-course/ this author explain everything its best js till date according to me.