What is the best way to purchase crypto with euros to minimize fees and maximize profits?

As a recent crypto buyer, I am confronted with several factors I didn't know about. I am using Kraken right now, not Kraken pro but standard version. When I went to make a purchase, firstly I was confronted to the fees, which were acceptable. But then I noticed that the price that was asked for BTC was very significant from the market price, by about 500 euros. I learned that this is the spread. In this version of Kraken (mobile app), my only option seems to press "buy" crypto, then I am sent to a screen where I input the amount and then I am shown the new price of the BTC which I guess includes the spread. Is there a more efficient way to buy crypto for long term holding?