We study AT2024kmq and AT2024lhc, two tidal disruption events (TDEs) with blue featureless spectra associated with high-mass black holes ((Formula presented)). Both events show optical precursors consistent with shock dissipation from stream self-intersection. Their X-ray emission is luminous ((Formula presented)), highly variable (with minimum observed variability time-scales of 1.3 and 4.8 h for factor of ∼3 flux changes), long-lasting (>1 yr), emerging no later than the optical peak, and well characterized by power laws with (Formula presented) (where (Formula presented)). The X-ray properties and radio non-detections support a compact corona ((Formula presented)) producing Comptonized X-ray emission. Using all published featureless TDEs, we find statistically significant bimodality in the distribution of their peak ultraviolet/optical blackbody luminosities and radii. We assemble a comparison TDE sample with early-time X-ray observations with eROSITA, in which we find different (Formula presented) distributions in TDEs with different X-ray spectral evolution properties: low-mass black holes ((Formula presented)) remain soft ((Formula presented)) within (Formula presented) yr, intermediate masses ((Formula presented)) transition from soft to hard at (Formula presented) 1 yr, while high masses ((Formula presented)) are hard ((Formula presented)) from the outset. We interpret this result as evidence that the soft-to-hard state transition in TDEs occurs at the critical threshold of (Formula presented) (similar to X-ray binaries), using the fact that the transition time-scale predicted by simple disc theory scales with black hole mass as (Formula presented).