US is stopping China to increase their DRAM and flash production as they would, by forbidding everybody to sell modern semiconductor manufacturing equipment and consumables to China.
China is increasing their production of DDR5 and SSDs, but much more slowly than it would have been possible in a free market.
The current prices for DRAM and SSDs would have never happened if USA had not started to sabotage the Chinese memory industry a few years ago, presumably because Micron wanted to eliminate their competition.
The US sanctions against memory producers have started exactly when Apple was considering the use of Chinese memories in their smartphones, so Apple had to cancel their plans.
The claims that the sanctions against the Chinese memory producers have anything to do with US "national security" or with military applications are just a big shameless lie.
Military applications are content with older memories, which China can produce in sufficient amounts. The SOTA DRAM modules and SSDs are more important for consumer products and the US "sanctions" have the only purpose of maintaining artificially high prices for the consumer products, which steals money from millions of people all over the world.