In a hypothetical descent into the Sun, what stops an object from hitting a hard bottom?

The force of buoyancy exactly counterbalances the downward pull of gravity

If one could survive the heat and descend past the photosphere, the journey would not end by impacting a solid center, as might occur on a planet. Instead, as descent continues, the surrounding plasma becomes progressively compressed and much denser. Eventually, an object will reach a specific depth where the density of the surrounding superheated stellar material perfectly matches the density of the object itself. At this point, the upward force generated by buoyancy precisely negates the downward acceleration caused by gravity, resulting in the object ceasing its fall and achieving a state of suspended animation or effective floating within the fluid medium.