I’ve posted this before but I really do think it bears repeating:
Rape is Rape.
And there should be a single, flat (long) sentence for it.
But rapists should also always be charged with the other crimes they commit during the course of the rape - coercion, detaining or restraining someone against their will, threatening behaviour with a knife, assault by hitting or slapping or punching, etc.
Every one of those should be a separate charge brought against the rapist with a separate sentence.
There are so many violent crimes that go along with rape but rape is the only one that the perpetrator is charged (and then only if you are ‘lucky’).