Just to add to the list of possible solutions there’s the lattice method. Add a lattice. Add a lattice modifier to the mesh and point to the lattice. Then adjust the lattice’s vertices in edit mode. You can add more cuts to the lattice as needed. Also proportional editing works with it too. Note: this method will probably be better for seat and back of chair, but it’s another arrow for your quiver of tools to think about.
