The horizontal tabulation character moves the cursor to the next column which is a multiple of the tabulation length. See the examples here: https://en.m.wikipedia.org/wiki/Tab_key

Yes

Clearly the whitespace produced by each tab character has a different length.

No, each tab has the same size, the text rendered over the top of the tabs are not the same size.

Always remember the golden rule: Tabs for indentation, spaces for alignment.