Risks of opening a short iron fly, then rolling untested short leg back to 50 delta

Hypothetical:

SPX 7DTE short iron fly, sell call and put at 7400, buy wings 50 points out. Max profit $4,200, max loss $760.

SPX stays within breakeven, do nothing.

SPX goes down significantly next day. Call side is worth a fraction of credit. Put side deep ITM, near max loss. Roll call side back to 50 delta, same expiration.

SPX goes down again next day, don’t lose much more on put side, gain some again on call side. Or SPX goes up next day, put side gains, call side loses less. Then start over.

I know it’s not that easy, so what am I missing?