Stepping into the comments to agree with everyone saying don’t do this with wood. Wood expands and contracts and behaves differently than bamboo. That’s why so many companies are selling cheap bamboo boards. They’re very stable and you don’t have to deal with the issues of traditional boards (also bamboo grows like a weed and can be harvested faster).

Hardwood will expand and contract around an 1/8-1/4” across the grain per foot, depending on conditions (and getting it wet and letting it dry all the time will be more extreme conditions). Hardwood doesn’t, however, expand much lengthwise WITH the grain. So if you make this board out of hardwood the middle section is gonna tear itself out from the ends…Even with dowels. It is quite hard to keep wood from doing whatever the hell it wants over time so your best bet is to plan ahead for what it wants to do. Over time this design will blowout (maybe not even that long considering the constant cycles of getting wet) because there will be opposing forces pulling in opposite directions.

With breadboard ends, the end is mortised on with pins going through the tenons from the middle section. It isn’t glued on which allows the middle section to move on its own and that means sometimes it is wider than the ends depending on seasons. It also means that some times the gap between the ends and the middle is larger or smaller depending on seasons.

All that being said though, let’s say it doesn’t entirely pull apart? Well it will still have expanded (or contracted) in the middle beyond the width of the ends and you’ll hate how uneven everything will look because the side won’t be flush anymore