What product to use on wood to keep the natural look?

https://www.minwax.com/how-to-finish-wood/

Minwax poly should work for this piece. Wipe all the dust off and give it about 3 thin coats--sanding lightly between the first and second coats. Poly comes in several different finishes. You could use spray poly on this piece--no brush marks that way.

Polyurethane. It comes in various finishes from flat to gloss.

if you want to keep it looking natural, rub in coconut oil. cheap and very effective, good luck and let us all know what you did in the end and how it turned out. stay safe

Bees wax or mineral oil

that is beautiful. I use a product called Restor a finish. Its just a conditioner that cleans, and they have a bees wax finish if you want to seal it for easier cleaning. It doesn't make it shiny, the conditioner just brings out the color and grain of the wood, and the wax just helps it stay conditioned longer

Clear Wax

Do you want it to be shiney or just protected? I used cutting board conditioner for mine cuz thats what i had on hand, but i dont think you can pour epoxy over it after that's been done so think about what you want it to be like long term before you put anything on it

You could use a clear varathane either in a low, semi or high gloss

Use any flat finish sealer. Flat is important if you want it to look the most natural.

I have used mineral oil and olive oil on my wood countertops. Both work fine to protect the wood. I do this twice a year. I have read that coconut oil works fine too. Let the oil soak in overnight. Rub off any remaining oil with a clean, lint free rag. I use cut up t-shirts.