For testing it is better to start with a very small bankroll. You will almost always lose first. Only when you grope your trading strategy is it worth making a weighty deposit. The deposit should allow you to meet the expected value of your trading, which will satisfy you.
When I'm also new in bitmex, I deposited small amount of money for the testing stage only. I practiced for that capital until I have learned the movements of indicators, the chart and the volume, etc. Then when I have decided to take it to the next level, I have deposited enough capital the amount that I can still managed even if I lose.
Leverage trading is not the usual trading yoh are thinking, OP. So, I suggest you do the practice in bitmex testnet first. Then, deposit maybe around $50-$100 first then you may add up higher amount if you gained confidence and knowledge.