For a (very luminous) hot star, this can compete with gravity…but note the 1/R 2 dependence, if a rad > a grav, a star would blow itself completely apart.
But note, free electron opacity, and the associated Thompson scattering, can be significantly augmented by absorption of photons in spectral lines - atoms act like a resonance chamber for electrons: a bound electron can be ‘driven’ much more efficiently by light than a free one (i.e. it has a much larger cross section), but it can only be driven by light with a very specific frequency.