Apply for the non-o outside of Thailand. You get 90 days when you arrive on the visa - go to immigration and get a residence certificate, get a Thai phone number and open your Thai bank account
The best option for you at this point is the DTV. You can work online and you get 180 days every time you enter Thailand. You need to have the equivalent of 500k Thai baht in any bank (just under 16k USD) as opposed to 800k (almost 26k USD - which must be transferred to a Thai bank) for the retirement visa and you can't work in Thailand you're on the retirement visa.
Side note: your so-called consultant must not know much about Thailand visas if they spent an hour and it's still not clear what visa you should focus on. Given the information you provided the DTV is clearly your only option. (Before anyone mentions the LTR, she clearly doesn't qualify and the retirement visa won't allow her to continue to work)
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