My understanding is that 1.75% of 10 euros is 0.175 euros which being less than 0.46 euros will cost you a charge of 0.46 euros. (Plus the 10 of course.)
My understanding is that 1.75% of 100 euros is 1.75 euros which being more than 0.46 euros will cost you a charge of 1.75 euros. (Plus the 100 of course.)
I never use a debit card abroad due to the hidden loading charges. Use a credit card. Santander Zero is OK. I did apply for a Post Office card but they wanted me to phone them every time I went abroad (which was ridiculous as I spend half of my life abroad).