I need advice on a really silly issue. I bought an old house that had “wing walls” as part of a floor to ceiling built in for old tube TVs. I cut down these walls, but kept the bottom of them to create a new built in, with a wood top and cabinet doors. The problem is that when we cut the walls down, the drywall got a little mangled and now there about a 1/2” gap under the wood top (there’s a 2x4 base that’s structurally sound for the top, this is just an aesthetic issue). The outside of the vanity will be wrapped in paneling, so the gap there doesn’t matter. But for the inside, how should I fix this gap? It’s too big for caulk and I just can’t think of alternative. Anything other than drywall mud?