Prop firms that behave like Ninjatrader Sim accounts

I keep running into the problem of my strategies performing well using Ninjatrader’s simulation accounts in a live market, and then when I switch over to my Apex prop firm account using a Rithmic connection, that the fills are more conservative than the NT sim and that my strategy can behave entirely different using Rithmic.

Since with prop firms, you start out trading a sim account anyway, I don’t see why my practice sim account can’t behave like the prop firm account. Has anyone signed up for a Rithmic paper trading account and compared that to a prop firm account using Rithmic?