Attempting a sub 20 5K (following 500km of steady running)

I hadn't run a sub 20 5K for nearly 2 years. After an injury in 2019, it had been a long recovery process, slowly building back up and chipping away at the 5K parkrun time. Slowly, this time came down and down until at the back end of 2020, I ran surprisingly close to the 20 minute barrier. And so, once I’d run the 500km challenge at the start of the new year, I knew, that maybe, just maybe I was finally ready to break the barrier that had eluded me for nearly 2 years. Can running 500km slow, help with running 5km fast?