Sometimes the suggested line is red for a short length when I don’t need to brake?
Not to worry, you will learn that there are a few shortcomings in the intelligence of the “suggested line” but on the whole it is pretty accurate. In particular, the suggested line is deliberately not the “best” line, since it intended to be relatively easy for non-expert drivers to follow. Because of that, the speeds associated with it may be slower than those attainable for the “faster” line that you may be driving. Learn the few spots where the suggested line is overly-conservative and live with it.