The two ways I'd go about this include one that you already tried: sculpting. Let me offer a few suggestions in case any help you:
First, duplicate your model. Work on a high poly copy of it (we'll discuss how to increase the resolution in the next suggestion: don't use Subdivision modifiers)
Use Dyntopo and/or Remesh (found at the top-right of the Sculpting UI:
Remesh will cut extra geometry into your shape using a voxel grid of a resolution you define when you go into the menu: the lower the number, the higher the detail level.
Dyntopo is fun! it dynamically adds extra detail (at a rate which you can, again, define) while you sculpt. Areas you've sculpted over will become denser (or less dense) with vertices while you go.
With this extra detail, you should be at your liberty to study the material you want to mimic and cut in your wooden detailing.
As Moonboots said in the comments, you could use a texture with your sculpting brush to help you stamp detail onto your surface.
The other suggestion (which Moonboots beat me to with their comment sent while I was typing :P) is to use a texture to add the details in. If you find a wooden texture you like online, it'll probably come with a normal and/or displacement map which can do the same thing, but using the object's material as opposed to helping you change its geometry.
If you're using a displacement map, fair warning: That (to my knowledge, please correct me if anyone knows better) only works in Cycles, and you have to make sure it's enabled in the material settings or it won't work:
A third suggestion (thanks, Moonboots!) is to use the Multiresolution modifier. This essentially streamlines the process of keeping a low-poly mesh while working on a high poly mesh to sculpt with.
I'm not as familiar with it myself, but you can use it to set your subdivision level, method (simple or linear (smooth)), then sculpt in high-poly without losing your low-poly mesh underneath. You can then also use the modifier to bake your normal map from the high-poly sculpt. Learn more here: https://docs.blender.org/manual/en/latest/modeling/modifiers/generate/multiresolution.html