sign rot issues

My town has asked me to repair 4 6'x4' "Welcome" signs. They are 3 years old, sandblasted and painted, made of cypress, and well maintained. The problem is the sign maker obviously didn't know about wood movement. The 2x8ish boards are running horizontal and they are heavily screwed to vertical bracing that attaches to the pole in the ground. The wood has split pretty heavily and that's where the water is reeking havoc. Pancake looking mushrooms are growing but it the rot isn't out of hand yet.

My first thought is a fungicide then filling the cracks with penetrating epoxy, caulk, and repaint, but I'm worried this thing is just going to crack somewhere else. Do I need to just have them brought to my shop and address the wood movement issue or do you sign guys have any suggestions?
Thanks

I would fill the open cracks, and holes . Then cover the sign with light canvas glued down . Wrap the edges too , all around.
Then paint it. Old method that still works . But it’s out of style. Was even on the hulls of wooden boats and ships .