My great uncle, who had been on dialysis for a couple of years chose to take himself off of it. He and we knew he’d have about a week to live because of his decision. He was assured by a priest that this was not suicide and not a sin, which was a comfort to him.I know this is not the same as choosing euthanasia, but he was choosing to let himself die so it is pretty close. Providing comfort to the dying is something that priests are supposed to do.
It's not "pretty close". That's a completely different scenario.
That's always been the case.
What you can't do, is murder yourself or set somebody else up to murder you.
Cutting off somebody's nutrition/hydration to make them die faster, for instance is euthanasia. Taking a deliberately lethal drug overdose is euthanasia. Which is murder.