What about the old school processors like Authorize.net and Cybersource? It has been over a decade since I worked with them, so not sure what they are like now.
Braintree is now essentially paypal, so that is off the list. Adyen is good but can be strict with what businesses they support.
In short, i recommend using local providers, not these multinationals. Each country has a bunch of them, so there is plenty of choices, they are just not world renown brands.
The most obvious one for processor to merchant is chargebacks. The window fo those can be up to 6 months.
Bank statements might also be used for fraud prevention and kyc requirements.
Disclaimer: I used to work at stripe but not in this area and I don’t know the specifics of why Stripe is asking for these documents.
In short, i recommend using local providers, not these multinationals. Each country has a bunch of them, so there is plenty of choices, they are just not world renown brands.