Why not the Cayman Islands? I was involved years ago in a 'distributed company' (US, Colombia, Brazil) that was offering a service to the Portuguese-speaking world (Brazil, Portugal) and we were registered in the Caymans. Things worked out pretty well and the only trouble I had relative to the administration was that my name was on some paperwork that went to vendors and I'd sometimes get calls from vendors who would…
I find there's too little open information on how for a software company to do things properly in classic off-shore jurisdictions. Everything on the web related to this seems shady so I don't know what to believe. Things like: are there online payment processors that work with Cayman Islands? Where will I be able to open a bank account? and more - are not clear. I'm sure there are use cases for tax havens, but for me…
If you're selling digital products, it's easier to use an online reseller (eg; PaymentWall, Gate2Shop, etc) but if you want to use your own processor, you will have to set up a merchant account which is a long and tiresome process.
I think 2checkout and Payza still allow offshore companies.
As for bank accounts, you're usually given a list of bank accounts from the same people who you purchased the company formation from. Loyalbank.com is a popular one, they give you a UK bank account.