The real problem is that fusion hasn’t even been shown to be physically possible at scales that won’t blow up large cities. And by this I don’t mean that you can get DT or DD to fuse as isolated events and produce energy. We have been doing those experiments for nigh on a century. The issue is whether you can confine such reactions in a controlled self-sustaining configuration so that producing net energy would even be possible.
What we have learned over the last two decades is a lot of the physics reasons why it is all very very complicated [it’s called plasma instabilities, and related to the problem of trying to get a glass of water not to pour out when you tip it over.
A problem with so many discussions about technical matters here and other places is that people with little understanding believe what they have read from people and organizations with their own agendas and it becomes ingrained and internalized. Our own resident fusion “expert” starts his threads with a warning to those whose view are not in lock step with his own to not participate. Amazing!