It boils down to a simple

It boils down to a simple formula, direct/reverberant sound ratio. The only way to improve it is to get the mic closer to the source (direct sound), either with a wireless lavalier (you can get fairly decent ones for about $200) or holding a directional mic just out of frame on a fishpole. No amount of post-processing can truly get rid of that reverberant sound once recorded, at least none that I’ve discovered in 30 years of radio production.