The way the system is implemented in Spain (not all sites use it sadly) is simply like 2FA, when you attempt to make the purchase the bank sends a sms or notification through their app with a code you need to input to confirm the order. Or is 2FA annoying as well for you? I know some people hate it.

I would have no problems with 2FA of the kind you described for banks. But such a system is not available here. You have to basically do a full login authentication here.

I do hate 2FA. I like it, but I hate using it. I've stopped posting on some forums/using services. I didn't actively quit them, but when the service had logged me out and it asked me for the 2FA code, I winced and went to go do something else. Over time this happened enough that at some point I just didn't visit the site anymore.

Really? What makes you so opposed to your bank? If their authorisation system is stupid, you can switch to a better bank.

Personally, I find this system a lot less painful than having to type in my credit card number. And it's a lot safer.

In my country every bank has the exact same authorization methods available.