I don’t know payments infrastructure super well, but reading your comment it makes me wonder if what you are talking about is related to the card woes that I had when I lived there in 2018. Not having a Swedish bank account and paying for larger sums with my American credit card would often trigger declines and I would have to contact my card issuer to authorize the payment to go through frequently. I specifically remember having a lot of trouble whenever I would pay a company that used the Swedish company called “DIBS” to authorize my payment.