tokamak technology is old and while the chinese claim of 100m is certainly on the high side, it is the target temperature that they all aspire to.
One in UK recently got to 15m
https://newatlas.com/milestone-temperature-sun-tokamak-energy-nuclear/54968/
The chinese tokamak did claim to reach 50M a couple of years back and to sustain in for 102 seconds
https://newatlas.com/china-fusion-reactor-plasma/41729/
so I would rate the current claim of 100m as possible.
The quest for sustainable fusion is a valuable one, perfectly understandable the chinese would throw some of their wealth at it.
