Few missing points in your post. 140 is not a formality. There is no Perm for Eb1. Employment based category means employer has the full authority to decide what category you belong to based on the job you are performing and not necessarily your qualifications.
In a normal scenario downgrades should not happen. It is happening because the people who did Eb2 originally did not qualify for it and now running and applying in regular category when originally they claimed to be exceptional Perm and the skills not available in US.
Eb3-2 upgrade applies with a new perm, Eb2-3 uses the old perm which has excluded people who could not match the exceptional skill requirement. Now when applying for Eb3 the rules are happily ignored to the extend that person who points these are obnoxious and condescending.
What you did is nothing wrong, you had an underlying perm for your Eb3.
So people instead of trying to find fault in my line of thinking, realize the pandemic induced embassy closures might result in 150,000-175,000 visas to Eb category in 2022 from October 21. Once Eb1 is current the biggest beneficiary is going to be Eb2I.