Yes, you can do SIP in Mutual Fund’s and pledge the units you get to receive collateral margin for trading, when you don’t need collateral margin for trading you can unpledge them and redeem your investments.
In investment, risk and reward go hand in hand. There is nothing as safe investment, every asset comes with inherent risk.
There are low risk products like Liquid and Overnight funds which you can explore. Would suggest you to learn more about them and make your own informed decision.
You can learn more on Liquid ETF’s here:
There’s also this module on Varsity which explores Debt funds in detail, do go through this for more information.