Basically as long as you don’t link your bank account with your social media accounts in any way, you’ll be fine. Basically don’t put your real name on your social media accounts, which no doubt you don’t do anyways. Don’t for example add bank information to say a Google account linked to that social media account.

The bank only sees the information you provide it, which is where you send your money and where it comes from. A bank cannot rat you out unless you are sending or receiving money from something illegal in your country.

A government investigating you on say social media might try to obtain information about your account to eventually tie said account to a real person. For example, you might use a Gmail to sign up to a queer site, and that google account might have bank information if you have Google bank information. Then the government will use said bank information to identify you. Just don’t put your bank information on anything linked to your social media accounts.

The bank can see your transaction. They may be part of a mandatory (or voluntary) reporting scheme.

The bank will not in general know about other things you do that don’t involve financial transactions.

Yes. If your country is authoritarian use cryptocurrency such as Monero. Even Bitcoin can be much better.

The bank would know the amount, the merchant and other details even if it’s a merchant from abroad. The bank might have a duty to report certain transactions or could be forced to give out a record. Other international payment process or foreign banks will generally not refuse a request if it comes from a country government you are a citizen of.

You can use crypto to buy gift cards to shop at regular retailers. This is your safest bet if you’re concerned about a state surveillance of your transactions.

I Am Not A Lawyer : I presume your best chance of anonymisation will probably be crypto accounts. But even then, platforms must register as authorized banking institutions with ID verification to be able to operate. And I suspect the local state can access that data, for example to track tax evasion.

But you also don’t want unauthorized platforms because who knows what will happen to your money.

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