if you are required to file a tax return then the legal onus is on you to self declare your remittances. The Revenue Department expect truthful returns. Make of that what you will.
you are confusing two separate visas and two separate processes:
Non O: Can be obtained from home embassy or in country. 90 days on entry. Funds can be from home country if obtained from embassy. Once in Thailand you need to open bank account and deposit funds within the first 30 days to season the funds in preparation for apply for a 1 yr extension of stay. The 1 yr extension can be applied for with between 45-30 days left, office dependent, on your original 90 day entry.
Non OA: Can only be obtained at home embassy, not available in country. Funds only from home country. Gives 1 year multiple entries to Thailand. Carries additional requirements including police check and health insurance. If you exit and re-enter just before the visa expires as long as you have health insurance you can get almost two years out of this visa. After the two years if you want to extend further then you need to have funds in Thailand to do so or you exit and re apply at home country embassy using home country funds for another OA visa.
You become Thai tax resident after 180 days inside Thailand in a calendar year. If you leave before the 180 days and then return nothing resets, you still are within the calendar year and will become tax resident on the 180th day of residence. Tax is only applied to remitted assessable income. If you don’t remit income there is no tax liability.