With sanctions they get free money to develop better chips.
== sanctions backfire
Also the money the spend on top is mostly domestic. They can build some more powerplants to run less efficient chips. They can pay their workers and their developers to build it.
Making it cost more is keeping them from being as competitive — which is the point of sanctions.
Huawei already designed and developed its own chips before sanctions, and SMIC is developing their next node before sanctions.
Whether sanctions work or not is another matter
Sure, but China has started dumping a lot of money into competing with ASML as a result of the sanctions. And no, they are not going the super complicated route of firing lasers at drops of tin to get EUV. They are trying to sidestep that costly complexity, and if they are successful they'll be providing equipment to the top chip producers (around the world or just their own).
Huawei was going to work on GPUs anyway, SMIC was going to fab chips anyway. How much of the total GPU compute is the result of increased investment after sanctions, and how much was already planned? And how does it compare to the alternative of importing Nvidia GPUs for the same amount of money?
Unless Huawei is getting better performance per dollar than Nvidia, this is them implementing a costly workaround, which is the point of sanctions: increasing cost.