Risk calculation (Market Order)

My trading ist on the M15/M1, so it is very fast. I analyse on TradingView and copy my Stop loss from there. Then I quickly have to calculate my risk which is 0.5% in this case 500$.

So what I did was put the Stop loss in and then I modified the Lot size until it was around 500$ (517$) as you can see on the right of the screenshot.

After I placed the order the Loss is way higher in this case over 600$, which is extreme with the account size I trade live, and not only that but also my Stop Loss 1.1760 was modified to 1.17601.

Why is this what I did wrong??

I use 0.5% every trade and have a fix SL, so I want cTrader to tell me quickly what Lotsize I need for that EXAKT STOP LOSS and the EXAKT amount of RISK... NOT MORE NOT LESS... PLEASE HELP