Is there a way to guarantee that an order gets filled at a set price or lower?

Sorry if this is a dumb question, but I’m new to the stock market.

From what I understand, a limit order will guarantee that a buy or sell order is filled at the limit price or above, but a stop order just sends in a market order when the stop price is hit, so the order could be filled in above or below the stop.

Is there a way to guarantee an order is filled at or below a set price? Or am I misunderstanding what a stop order is?

Thanks in advance