  Pre-main sequence disk accretion is pivotal in determining the final stellar
properties and the early conditions for close-in planets. We aim to establish
the impact of internal (stellar mass) and external (radiation field) parameters
on disk evolution in the Lagoon Nebula massive star-forming region. We employ
simultaneous $u,g,r,i,H\alpha$ time series photometry, archival infrared data,
and high-precision $K2$ light curves, to derive stellar, disk, and accretion
properties for 1012 Lagoon Nebula members. Of all young stars in the Lagoon
Nebula, we estimate $34\%-37\%$ have inner disks traceable down to $\sim 12$
$\mu$m, while $38\%-41\%$ are actively accreting. We detect disks $\sim$1.5
times more frequently around G/K/M stars than higher-mass stars, which appear
to deplete their inner disks on shorter timescales. We find tentative evidence
for faster disk evolution in the central regions of the Lagoon Nebula, where
the bulk of the O/B population is located. Conversely, disks appear to last
longer at its outskirts, where the measured fraction of disk-bearing stars
tends to exceed those of accreting and disk-free stars. The derived mass
accretion rates show a non-uniform dependence on stellar mass between $\sim
0.2-5$ $M_\odot$. In addition, the typical accretion rates appear to differ
across the Lagoon Nebula extension, with values two times lower in the core
region than at its periphery. Finally, we detect tentative density gradients in
the accretion shocks, with lags in the appearance of brightness features as a
function of wavelength that can amount to $\sim7\%-30\%$ of the rotation
period.
