This video walks through the tech in a very explainable way, and the interviewer asks a lot of pointed questions.
To your questions
> 1) keep the hole from collapsing
They are vaporizing the rock which turns everythingeft into an obsidian like substance.
> 2) remove the volume of rock required to continue going down
As the rock is vaporized, they push nitrogen gas down the hole to cycle the vapor back to the surface
The video goes through the main challenges they have, like rate of penetration, power output and other small issues.
Will they be successful? Who knows, but the concept seems sound and the tech is proven. Can they do it at scale and consistently enough to change drilling worldwide? Who knows.