Sorry for the delay. I had to wait for our legal team to chime in. This is what they say...
The terms and conditions that govern access and use of PDF Embed API are the General Terms of Use (https://www.adobe.com/legal/terms.html) along with the Additional Terms for Adobe Developer (https://wwwimages2.adobe.com/content/dam/cc/en/legal/servicetou/Adobe-Developer-Additional-Terms_en-US_20230822.pdf).
Your understanding of Section 20.1.b is correct.
However, our Additional Terms for Adobe Developer also prohibits access of our NA server from China under Section 6.17.
6.17 Regional Service Limitations. Unless use in a Restricted Country is specifically authorized by Adobe, you are not permitted to use any Developer Tools in any Restricted Country or to enable users in a Restricted Country to use the Developer Software. “Restricted Country” means mainland China, Russia, and any other country where access or usage is restricted by local laws or is otherwise restricted pursuant to section 6.5 (Trade Controls).