If you are in your home country, best thing to do is apply for the 90 day non-o there. Then arrive Thailand go to immigration for a residency certificate (500bht) and then you should be able to open a bank account without any issues. They may want you to take out their 1 yr insurance for around 5000bht but hey there’s a price for everything here. Once your bank is set up, go to immigration and get the forms for an extension so you know what docs you need to gather. Once you are 45 days before the end of your 90 days visa, you can then apply for your 1 yr extension based on retirement.
I’ve heard this headache argument so many times. I find it myself and process was easy. All done in 4 visits for both the Non-O and then the extension 2.5 months later. I’d say a total of 2 hrs in all. Nothing difficult about the paperwork or the process.