This is outside the scope of specific Thai Visa/Thai immigration advice, but pertains directly to obtaining a Non-O based on Embassy-certified Affidavit of Income:
In my opinion, you would take that « Déclaration de revenus (pour le visa/permis de séjour en Thaïlande) » that the French Embassy in Bangkok just certified and further do a legalisation of that Déclaration, which, of course, would complete the legalisation at Thailand MFA (Ministry of Foreign Affairs)....
Well, considering many countries and many airlines, but not Thai immigration, require a passport valid for at least 6 months, the easiest thing to do is renew your passport.
If it is a U.S. passport, then U.S. passport processing times have come way down and are much faster nowadays
As the first DTV Visas were issued late July 2024, the earliest those who were issued those early visas and quickly used them to enter Thailand and stayed in Thailand throughout that period to get to 180 days would be late January 2025....