Often, like with Kingfisher Airlines which was the largest Indian carrier to go bankrupt, the "purchase" is really a lease for the aircraft and the leasing company actually buys the planes. So the airline defaults on the lease payments, leaving the leasing company holding the bag.
Airbus is building 30-ish A320 NEOs per month, and already have a backlog of 1,500 aircraft. Adding another 500 to that backlog means that deliveries will be pushed way out.
In addition to your comments
“the aircraft will be received between 2030 and 2035”
That is long term planning leaving room for so much to go wrong in terms of wars, world wide depression, man made depopulation programs (more pandemics) to name a few possibilities.