robinhood box spread limitations – workaround?

Robinhood won't let you do a box spread on SPX. However, I can do an almost box spread, by shifting one of the legs up or down by 5 points.

Is there a way to do this in a way that almost eliminates the risk? Like shifting one leg, opening the spread, and then immediately doing another transaction to offset the leg that shifted so you're just about neutral.

Or just take a small risk the market moves in a way that results in a profit or a loss, but set one of the legs in a way that the risk of a loss is very very tiny

Does anyone have any suggestions?