That is not trading that is gambling and bad gambleing at that. You are essentially throwing all your money at the market and hoping it goes well.
If you trade the full amount you are capable of on one trade the trade will not have enough room to breathe. when you get a winning trade it doesn’t automatically go positive, often it will go many pips against you before it goes where you think it may.
Lets say you have a $100 dollar micro account with 400/1 leverage. Thinking it’s a good idea to trade as large as you can because you will make the most money you trade the most you can on one trade.
400/1 = 400x100 = lot size of 40000. Rounding off each pip would be worth $4.
For you to get a margin call or lose your whole account the trade would only have to go against you 25 pips. Which is nothing for breathing room. Price can spike 25 pips.
You may get lucky once or twice, but sooner or later trading this way you will get a margin call and zero out your account.
If you know how to manage your risk and only risk a small amount of your account you can compound up when you win or down when you lose and never come close to a margin call.
P.S. using a margin call as stop loss would not protect your, “unused margin,” if you trade the highest amount your account is capable of in one trade it is entirely possible, actually probable, that you will lose your whole account in just one trade.
P.P.S. The risk reward ratio is not increased by risking more? How would that work? Sorry, no, you are tottally wrong on thinking it seems this way.
The whole point of risk reward is that you have an edge and know that maybe 6 of 10 trades wins. So, you risk a small amount on each trade and give up a small amount on the losses. You are essentially staying in the market so your wins can hit. This is also the reason the winners have to be as big as the losers or better. 6 winning trades out of 10 is useless if the winners made just a few pips and all the losers lost dozens of pips.
I suggest doing some searches on this subject. I alone have already posted on this very subject a couple times this week.