IF you use epoxy and the gap is more than VERY small, and your weather goes from very hot to very cold, the coefficient of expansion of the epoxy and the wood is different and over time the crack will get bigger!!!!

When we were in Georgia this happened on some decking we had. After 2 years the crack was way worse then when I started.

If possible, I would suggest something like Resorcinol and clamping it to close the gap. If not clamps, maybe screws with bungs to hide the holes.

Greg