First sorry for the multiple posts, I could not go back and edit my last post.
You might have misunderstood how the DCF process works. It is easy to mistake as I did at first. But to your point, "any quarantine time required for traveling to the I-130 interview in China." I did not have to quarantine in China as I was already living in China. I hadn't even left the country for 3+ years. So all that was needed at the time was a Green CR code in the Chinese APP.
At first I contacted the USCIS office in Guangzhou and got this response
Please note that as of February 1, 2020, direct filing of Form I-130 with USCIS offices overseas is no longer available.*
Please review the following information on the USCIS website for instructions on filing Form I-130, including where to file: https://www.uscis.gov/i-130
*USCIS issued guidance, effective Feb 1, 2020, delegating authority to the Department of State (DOS) to accept and adjudicate a Form I-130 filed by a U.S. citizen petitioner for an immediate relative if the petitioner establishes exceptional circumstances or falls under blanket authorization criteria defined by USCIS. This guidance, which applies even in countries with a USCIS presence, can be found in the USCIS Policy Manual, Volume 6, Part B, Chapter 3.
As of Feb 1, 2020, USCIS will no longer accept and adjudicate routine Form I-130 petitions at its remaining international field offices. Petitioners residing overseas who are unable to file with DOS must file Form I-130 by mail with the USCIS lockbox facility in Dallas, or online using the USCIS website.
Sincerely,
USCIS Guangzhou
However, later that day I received a second email from USCIS Guangzhou
You may find more information on eligibility to file an I-130 petition at the US Consulate Guangzhou based on “exceptional circumstances”. If you meet the “exceptional circumstances” standard, you may contact the Immigrant Visa section at https://china.usembassy-china.org.cn/visas/immigrant-visas/immigrant-visa-unit-question/
Sincerely,
USCIS Guangzhou
Using this link I was ably to apply for DCF with the Guangzhou embassy. After writing a basic description of my circumstance to them, I received an email back, requesting more information.
Dear petitioner,
Thank you for your inquiry. If you would like to ask Consulate Guangzhou’s Immigrant Visa Unit to accept an I-130 for direct filing in Guangzhou, please respond with detailed information about your situation and the background of your petition.
Please explain the reason you would like to file directly with the Consulate and are unable to file directly with USCIS in the United States.
Have you already filed an I-130 for your beneficiary directly with USCIS?
Please confirm that both you and the beneficiary are currently present in China, and will be able to remain in China for the duration of the immigrant visa petition filing and immigrant visa application process.
Hope this help you.