There are plenty of mistakes due to which we are struggling, you have shared some of them and I would like to add one another mistake that most of the people are failing due to using big lot size and trading with big target of profit
I agree. I prefer to aim for smaller but more secure profits while taking fewer risks.
As for sticking to one's strategy as a way to make profits on a regular basis - on principle I agree with that as well, but I think it's important to keep in mind that no strategy is 100% effective. The point is to find a strategy that that works more often that it doesn't, and then truly stick to it, while doing one's best to figure out under what circumstances said strategy fails so one can either improve it or avoid trading while using that strategy during those circumstances.