Quinn, you just have to make up your own mind. I coach sprints (I include the 800 in that category) in track and also coach XC. I am also a big promoter of my own screwball ideas. I have seen much success with relation to XC and 400m. Our Class A boys all-state XC runner ran a 50s 400m and a 23.7s 200m, he was a state medalist at 800m. He was no where near that fast last year. Our top 2 girls XC runners were our lead-off and anchor on our 4×4 team. One girl ran a 58.4 split and the other ran a 62s both top times on our teams. The top 2 returning girls on my XC team ran 63s and 65s respectively in 400m in only 2 races as 7th graders. The main thing is these kids worked their butts off, The top boy on my Middle School XC team ran a 54s 400m he finished 35th at the State XC meet, he had to scratch the 8th grade state meet 400m because of Pole Vault which he won by clearing 13-0 feet.
That said as KW would say “There is more than one way to skin a cat.”