Your local immigration office should be able to give you a conversion to a Non O (not all do) and from then onwards a yearly extension as long as you meet the financial requirements.
If you can’t then an agent will be able to help for a fee.
Each bank branch manager sets their own rules, so the fact one branch said they “don’t do this anymore” doesn’t mean another branch will. BB has its own issues at the moment so maybe best to avoid them anyway.
You fail to mention nationality but assuming you are from one of the 93 countries that would get a visa exempt entry. Currently that’s 60 days on entry and can extend once for 30 days if so. There is no 60 day extension.
If you enter visa exempt you’ll find it virtually impossible to open a bank account these days. An agent might be able to help you but DIY is almost impossible.
A better option is to apply for a Non O or Non OA visa prior to coming and then you’ll find opening the bank account way easier.
If you opt for the Non O then you’ll each need one and each would need their own funds in a bank account for the ongoing extensions. The advantage is you don’t need medical insurance.
If one of you gets the Non OA then the other can “piggyback” off that visa as a dependent so only one account of 800k needed. The disadvantage is the compulsory medical insurance which can be expensive depending on age.