Vertically align some text to top and some to bottom on same page

You're on the right track. Eliminate your Section Break and split your text into two paragraphs. Then in Page Layout settings select Justified for your vertical alignment. Anything in your top paragraph should orient to the top, anything in the second paragraph to the bottom. If you need new lines in these paragraphs, use a carriage return shift enter instead of just enter.

Note, this solution doesn't allow for very complex formatting on the page, so if you need a complex layout, you should consider options like Text Boxes or filling the between paragraph gap with "empty" paragraphs as placeholders.