Highly unlikely to be real.
If this concept had legs I would expect it to have been already gobbled up by one of the major aircraft manufacturers even while the company was in 'stealth mode'.
Not only it's supposed to be 70% more efficient, but it is supposed to be easier to construct. On another article(https://paxex.aero/se-aeronautics-fever-dream/) they are saying they have a "new construction technique" that can build a whole airframe in a week. New, unproven construction technique could be revolutionary in itself - and an uphill certification battle.
Oh and also the engines will be swappable in 30 minutes. And it's so efficient that even though it has two engines, only one will be in use at a time in cruise. So this means they will be close together. This is a safety concern.
Its economy class will be more comfortable than today's economy class too (how can you claim that, that's entirely up to the airlines, unless they won't offer other seating arrangements)
Lots of outlandish claims. Sure, the airline industry has only made very incremental developments over the past few decades and is overly conservative. Probably ripe for disruption. But to claim that you can suddenly leapfrog them on cost, efficiency, construction time and other verticals AT THE SAME TIME... sounds like snake oil to me.