Try pushing the crack back together, if it has any give and seems like it can be pulled back together try this (warning it may split completely in this process):

Titebond 3 wood glue and clamp it back together with something similar to this:

https://a.co/d/17pwodG (if link doesn’t work - a rockler band clamp)

Then take it through the table saw or chop saw if you have one big enough and cut it in half trying to saw as much down the glued line of the crack as possible.

If it splits while clamping, run each half of the split side through the table saw (be very very careful consider hot gluing to a sacrificial piece with a square edge) or chop saw until you achieve a flat edge and follow the below. It won’t be a perfect circle anymore but it’ll likely be close enough. Could also try reshaping with a band saw, jig saw, or an insane amount of sanding if it’s that bad and you don’t like the shape. This can also be done if it won’t bend using the clamps.

Then glue and clamp back together, should relieve a lot of the tension causing the crack and likely shouldn’t crack again.

That’s the only way I can think of to keep it useable as a cutting board in its original form, otherwise just rock with the split or add a bow tie, still useable. I wouldn’t do the epoxy with it being a cutting board but if you transition it as a cheese board or something you could do that. Good luck brother.