If you want to stay for a year you can apply for a one year Non O-A visa at home with proof of income/pension equal to 65K baht a month or funds equal to 800K baht.
For the Non O-A visa you’ll need a mandatory health insurance covering minimum 100K USD, a health certificate and a police check up as well.
Most convenient to apply for a 90 days initial Non O visa online through the embassy/consulate that serves your current location now. You can apply only with income/pension if you fulfill the required 65K baht a month OR funds equal to 800K baht. I don’t know your nationality, but you have a typical German, Austrian or Swiss name. If that do correspond with your passport remember you can apply for the one year extension of stay in Thailand only with a affidavit letter from your embassy in Bangkok (or consulate) confirming your income equal to minimum 65K baht a month. You therefore don’t need to prove any funds in a Thaibank now or in the future.
You’ll need to apply for a 90 days initial Non O visa in country first before you can apply for the one year extension of stay based on this visa. There’s no one year extension for visa exemption or tourist visa.
And I guess it also depends on the particular tax agreement your own country has with Thailand. For Norwegians as an example partial taxation to Thailand is an advantage. But we don’t have this 60+ plus fond as you mentioned.