I received the following response from Spotify support. It seems that even though there is not a Paysafecard symbol, I can add the Paysafecard as a regular credit card. Have not tried it yet, but should work. Only when you register as a new customer, is there a Paysafecard symbol in the payment options. A bit confusing!
————— We accept PaySafeCard as a payment method in Finland. Since it's a payment card, have it entered like a credit card as you normally would. To change your payment info, follow these steps: