Earlier quoted context omitted.
What are you using to backtest? Data you gathered yourself? Hardest part with backtesting in my experience has been trying to simulate successful buy/sell orders and the fees.
You can query Bittrex for some data, or you can find some data and a script from here https://github.com/gcarq/freqtrade/tree/master/freqtrade/tes... Couldn't you bake the fee into the application logic e.g. https://github.com/gcarq/freqtrade/blob/master/freqtrade/mai...
Strictly speaking, you should be incorporating level 2 order book data to properly gauge fees and simulate real world profits from your backtests.