I tested my EA for years back using only M1 open tick data and then run it on real account for two months and the results were pretty much the same we expected. We had about 5 trades a day, TP somewhere between 10-20 pips. Market orders only.
I used Forex Tester 2 for backtests because MT4 tester is so slow when you have more trades open (as we had). FT2 is about 10-100x faster depending how many open trades you have.
But it really depends on your strategy how to test it to get reliable results.
Sometimes it is favourable to just use bar close/open to do calculations because it filters out some spikes in tick data. And this speeds testing a lot!
Being Bearish or Bullish Makes No Difference