Yes cross country will help you develop a base. Google Clyde Hart, arguably the best 400 coach in the world. His runners have ranked #1 in the world 14 out of the last 19 years, are currently 1 and 3 on the all time world list and have won 3 of the last 4 Olympics and 6 of the last 8 World Championships.
Another of his athletes won the World Championships this year. Strategy Reach race speed as early as possible in first 50m cruise to 200m then accelerate steadily next 100m and hold form for last 100m Workouts done to rehearse strategy called EVENT workouts eg 3 x ( 350m rest 1min 100) 5min rest or Event 300s Which were run with first 50m very quick but then relaxing to go through first 200m and then the last 100 all out rest 10min between shorter later to maybe 5min. Aimed to have consistent stride frequency and length for duration of race - not a longer stride at end, Allow a shorter stride to just happen but maintain cadence.
Holding Form Improved by Strength Endurance Upper body ... more.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.