In todays highly competitive market the most challenging contingency for a buyer to have is an appraisal contingency. Buyers are competing with all cash offers. Why does that affect the sellers? When offers are over asking and above recent comparable sales, the appraiser is going to have difficulty bringing the value in at contract price. When that happens the buyer can walk or may not have enough funds to make up the difference. Then the seller has lost a buyer.
If a Buyer is not in a position to bring more money to the table, I would not advise going without an appraisal contingency. Therefore the chance of them getting their offer accepted is slim. They need to understand that.
If they have parents who can gift them money, or other funds, it would be one way to get over the appraisal contingency. Buyers also need to understand, this is a heated market, one we've been in before and that is how inflation occurs. If they are not comfortable with paying more than a property is worth in an appraiser's mind, they can wait. Waiting may mean paying more. Because as these properties close they will be the new value.
And in life, what goes up - goes down. We just don't know how high and how long this one will last.