Sure, if you have any personal bank account balance of at least 500k Baht ( USD $16k if applying at Thai Embassy/Consulates in USA), then you meet one of the main requirements for a Destination Thailand Visa (DTV)
a DTV Visa does not have any minimum income requirements, but minimum financial requirements (proof of funds)
Since, you are receiving monthly American federal Social Security RSDI benefits, it is most likely you would not apply via the Workcation/Remote Worker/Digital Nomad track ( i could be wrong.... ), but via the Thai Soft Power track of a DTV Visa....
No, at the Thai Consulate in Hong Kong, they have always required HKD $150,000.- since the DTV started in July 2024
Financial document:
Applicant must demonstrate his/her financial capability by presenting the 3-month bank statement or proof of income showing an account balance / income of at least 150,000 HKD or its equivalence in other legal currencies (national official currencies). The Consulate also accepts bank accounts from abroad, not just from Hong Kong, Macao or Thailand.
Normal DTV (non-dependents) Applicant must have his/her own bank accounts.
Well, yes, each of the nearly 80 Thai Immigration Office across the country do have discretion on their own requirements and interpretation of rules....
No, those on a Non-O Visa (Married to a Thai citizen) and Extension based on Marriage to a Thai Citizen can obtain a Thai Work Permit without the need for a Non-B Visa, as others have commented, businesses obscure this fact so that they have both your Non-B Visa and any Extension along with Work Permit tethered to them.
As with nearly all Thai E–Visas, any Thai Embassy/Consulate processing and deciding whether to issue a Thai E–Visa will look for proof of funds to be in an individual/personal account, not business account.
It is at the discretion of the Thai Embassy/Consulate whether they will entertain accepting business accounts or not, and from the experience and reports of many over the years for various Thai Visas and situations, = it's an individual/personal account
However, I will not say never as there might be specific, individual circumstances at a specific Thai Embassy/Consulate with a particular Thai consular official where it might work, but keep things simple and straightforward is always a good thing!