And while we talk about fusion, even when the energy output surpass the energy input and the reaction is stable enough, how to you harness the energy? Because the reaction happen within a vacuum, the only way is to capture expelled neutrons and make electricity from it somehow.

Yes, they forgot that part, so there will be further energy losses (at least 70%).

They also have to up the repetition rate from once a week to at least 1k /s.

Note that ASML lithography machines accurately dilate and irradiate molten tin droplets with lasers at ~ 50k /s.

https://www.asml.com/en/technology/lithography-principles/li...