I know in Germany murder is still murder if the murdered person consented to it.
Also, an autopsy isn't just "randomly cutting someone apart". The point of an autopsy is to determine a person's couse of death and doesn't just involve cutting the dead person open. You being alive means that an autopppsy, by definition, cannot be performed on you.
What you want is someone to mutilate and kill you. I'm pretty sure you can find someone willing to do that.
Side note: I think you overestimate how long you will stay conscious when the blood starts flowing, painkillers don't fix your brain running out of oxygen.
I know that Alice Weidel, co-chairwoman of the german right-wing extremist party AfD is openly gay and in a relationship with a woman from Sri Lanka. Fun fact: while she actively tries to abolish same-sex marriage in Germany, her partner advocated for the introduction of same-sex marriage in switzerland.