I would say the required documents should be your recent utility bill for current location and for freelancer status company incorporation docs along with a signed and stamped letter head stating that you can work from thailand, your personal bank accounts containing equivalent to 500k bt, also you can supplement with your company's statement, previous years tax return, invoices/ledger from from trading account should be sufficient, I know its a over kill but better be safe than sorry. If you are doubtful then you can go for soft power route, just search the group. No one can guarantee visa as different embassies have different policies. Also some embassies demand 500k bt equivalent is maintained through
***
/1 month and few are okay with only last balance in your personal bank account.
bartending and nursing are kinda restricted jobs for thais, I assume that you don't speak thai so very much likely you are gonna find jobs where you have to face public where 95% will be speaking thai, additionally those jobs pay very low so being an american the minimum salary to sponsor is 60k. In 60k they can find 2-3 eligible applicants for the same job. I suggest you should pick up some skills in which you can remote work, in order to keep you busy.
yes it's a glorified tourist visa just that it has validity of 5 years and you can stay 180 days per entry at a strech without extension, and one extension per entry is permitted. Even thai elite visa is also a tourist visa.
You can write up a cover letter explaining that you live off real estate income in Italy, you can attach property registration docs that are in your name, rental agreement and the taxes you file, I suppose that would be suffice for the embassies/consulates.
for 500k they really want it in the form of cash within a bank account that's too in your name though you can submit crypto docs as a supporting document. Many people have submitted their stock portfolio as a supporting document.