  The discovery of the charge density wave order (CDW) within a magnetically
ordered phase in the kagome lattice FeGe has provided a promising platform to
investigate intertwined degrees of freedom in kagome lattices. Recently, a
method based on post-annealing has been suggested to manipulate the CDW order
in kagome FeGe towards either long-range or suppressed orders. Here, we provide
a comprehensive comparison of the experimentally measured electronic structures
of FeGe crystals that have undergone different post-annealing procedures and
demonstrate the remarkable effectiveness on tuning the CDW gap without strong
perturbation on the underlying electronic structure. Moreover, we observe an
additional low temperature transition that only appears in crystals with a
long-range CDW order, which we associate with a lattice-spin coupled order. Our
work indicates a likely strong sensitivity of the CDW order to disorder in
FeGe, and provides evidence for strong coupling between the electronic,
lattice, and spin degrees of freedom in this kagome magnet.
