Think depends on how long ago. 20 years ago it was not so strict as now. Opened a bank account with no visa. And they where happy when I put in the money. So violating the law ? Think there is no real law for opening a bank account. Bank regulations ? Maybe now but sure not 15 / 20 years ago. Bank account opening rules where, and think they still are, on their web sites for a foreigner....
Well, if it's really only 1 year, then maybe look on the thai website in y'r home country if you can fulfill the requirements of a non imm O-A visa. Then you don't have to worry in Thailand besides every 90 days a notification from the Thai imm. Even possible to do that online. You don't need a Thai bank account. Should you want to stay longer you got a 'free year extension' after doing a border hop just before the visa expires. But....you have to have a health insurance for the whole year or the time you want to stay a bit longer on this extension. It's a bit more difficult to get this visa in y'r homecountry, (like a police clearance and health insurance) but then you are ready to go.
If you want to retire then I think best option is the non imm. O (Without 'A') so you can stay 90 days. After e.g. 60 days you can get a year extension but then you need a Thai bank account, 800k฿ in that bank etc. etc.
So for about 1 year only, I think if you can fulfill the requirements for the NON IMM. O-A visa, it's the most hustle free time in Thailand.
I don't know that restrictions of 50k฿ when transfering from a Thai bank to another Thai bank, or paying something. I think you have a limit within y'r app settings.
I don't know Krungsri, but for Kasikorn and Bangkok bank it's:
Kbank > "more" > set transaction limits
Bangkok bank > settings (upper right corner 'wheel') > Daily limits
Maybe check these settings in y'r app 🤷♂️
Long time ago, but that is with international transfers from y'r 'home bank' to a Thai bank and think not relevant with y'r remark, there where indeed limits set of 50k฿ with most Thai banks. Untill now I still think it is SCB, Kasikorn and Bangkok bank which don't have those limits. But as said, only aware of international transfers, not local.