I think it's important to understand the logic with the arguments on this.
The most basic premisees are a) that some lives are so full of suffering, and there is no hope for improvement, and it is cruel not to let people die, and b) people have the right to end their life. The rest follows logically.
You can see the way it plays out where these laws have passed. It starts that there are protections, people need to be approaching death, they need to be able to communicate their own decisions, they need to be mentally competent.
So the next step is that lobbyists say, well, what about the poor people who want assisted death but become demented or incapacitated? They need to be able to make provision ahead of time.
Then they say, well what about people who are suffering, there is no clear way to relieve it, but aren't going to die in the foreseeable future? Isn't that a terrible thing? So then that rule is removed, along with rules about not allowing it for mental illness, because after all, that is real suffering.
Then, what about people without capacity? Don't we have an obligation to help them if they are truly suffering? So then they start looking at allowing parents, guardians, or others to act on behalf of children or people with intellectual disabilities.
And if that sounds unlikely, consider that in Canada, a group of doctors reviewing these rules recommended that assisted death laws be extended to infants.
Here is an article - for context, the group, the College of Physicians and Surgeons is the group that manages doctors licencing, regulations, standards, etc, for the province of Quebec.
https://www.cbc.ca/news/politics/assisted-dying-carla-qualtrough-1.6625412
Basically, once you allow for those premises, it's very difficult to stop the protections being eaten away.