I have one that was custom molded but it looks like you can get OTC mouth guards as well.
It was either this, or they'd have had to pull adult teeth to make room for the remaining.
They do that procedure of small electric burn to the soft palate and/or back of the tongue - it supposedly creates scar tissue which firms those areas. Had it to the palate 14 years ago and snoring is still significantly lower - was told that the effect may be temporarily as/if the scar tissue goes away.
I don't think that surgery on the jaw itself should be an option in cases other than severe pain limiting function of the joint. If the teeth are crowded, remove a couple - that definitely seems like the choice with the least potential for complications that could essentially ruin someone's everyday life anyway.
When do you propose to do this? You can't do it until the final set of teeth have come in. If you do it later, then it might address the overcrowding of the teeth themselves, but it's too late to do anything about the size or shape of the jaw itself. Maybe you can affect the position/alignment of the jaw somewhat. That can be beneficial in many ways, but I'm not sure it would address the snoring issue.
Really its a weight/bmi thing from what I've read. All that fat presses down on the different soft areas of your throat and mouth. This causes the rattling and flapping which we hear as snoring.
Now I'm the proud owner of a gym membership and https://www.amazon.com/Meinl-Percussion-DDG-BOX-Didgeridoo-M.... All thumbs up here.
If you wake up tired and have low energy with daytime sleepiness try getting checked for sleep apnea. The home test is pretty easy (pulse oximeter followed by a slightly more involved test with a chest strap and a cannula).