Waiting days to get the results of your backtests? What on earth are you backtesting? I'd hazard a guess and suggest that you could improve your backtest time by adjusting your optimization so that it is fit for purpose. For example, you probably don't need to be optimizing a multiple-market, multiple-parameter machine learning strategy over many years of tick data.

Can you share a little about your strategy (eg how often it trades, bar period, how many parameters, overview of trade logic) and your current optimization and backtest setup?