I can add a bit more to this discussion. It is best to use a linear polyurethane (LP) coating over bare wood that has been encapsulated with epoxy resin. I have also used varnish (phenolic resin base mixed w/tung & linseed oil) to coat epoxy resin. It results in a slightly darker stain.
The oil based varnish stretches more than the wood, and the epoxy will stretch too.
In the future I’ll only use epoxy if I plan on sheathing or painting with LP, but I have not had a problem with either oil based enamel or clear varnish over wood that has been sealed with epoxy (kind of like using epoxy as the primer). I sand the epoxy with increasing grit sand paper, usually 80, then 100, 150, 220, & 330. I believe the advantage of LP over epoxy is because of a chemical bond but I can’t say for sure.
Some folks use the LP over the oil based varnish and claim it”s better UV protection and brighter. I can’t speak from experience on this approach.
It will be easier to strip it down again in the future with only oil based varnish. You’ll need a good respirator to avoid lung cancer and a lot of acetone and sand paper or a grinder to get the epoxy off if that is ever needed.
I have a solo12 dingy that shows the difference in varnish over bare wood vs. over epoxy, because I used epoxy as a sealing below the waterline. The difference is subtle. I’ll post a photo when I figure out where the wife hid the camera.