This vid is really great and knowledgeable.
Independent testing is a must but as he says, probably the most important and easiest test to prove it is indeed a solid state battery would have been to simply ask VTT to cut the cell in half so... why didn't they? I mean, they claim it's cheaper to produce.
So basically they're selling a 400 Wh/kg without Li that has all the hallmarks of a 300 Wh/kg Li battery. Best case scenario looks like it's a top NMC battery, with slightly better energy density than Molicel P60B (7%) and maybe able to charge twice as fast.
He's pointing out, as I did, that we'll need proof that all independent tests will be carried on the same cells (at least same cells chemistry), this is quite important.