Solvay's factory reported only 56 kilograms of SF₆ emissions for 2023 to Germany's industrial emissions register. The scientist's estimates are 500 times higher: around 30 tons. Its effect on the atmosphere is more than that of 700,000 tons of CO₂ due to the high global warming potential of SF₆, comparable to a coal-fired power plant.
So, in terms of how much they probably lied: really bad.
In terms of whether this one factory could significantly screw up climate: not as bad. Footprint is roughly the size of a large coal-burning plant going at full load.
They obviously have to fix their leaks + pay for their emissions + pay a large fine + show their internal documents to make it clear if this was intended.