Is the only source for ARM chips the big Western parts suppliers? If not, and you can get them from AliExpress or Crowd Supply, then, again, there's no difference in shipping between ARM and RISC-V chips.
A quick search for "arm chip" on AliExpress shows lots of results, so I don't think your argument refutes anything I said.
> A quick search for "arm chip" on AliExpress shows lots of results
Most of those are going to either be fake, or a clone with all kinds of weird compatibility issues. You might even get recycled chips, scavenged from e-waste.
You can buy STM32s from LCSC (Chinese equivalent of Digikey). They're probably not fake - LCSC is a fairly established trusted manufacturer.
China makes a huge majority of the world's electronics, and a big chunk of those will have ARM microcontrollers on them. Of course Chinese suppliers can get genuine ARM chips.
A quick search for "arm chip" on AliExpress shows lots of results, so I don't think your argument refutes anything I said.