Based on personal experience, yeah I think plant based eating works REALLY well for a lot of people. Then for others with predisposed genetic conditions around poor iron absorption… it can wreck their endurance sport careers lol I was vegan for 2 years. At first it was great. Same benefits you mention. Then suddenly… I couldn’t run a mile without a 205 HR and heaving/crying from frustration. It didn’t work for me. Not to say it wouldn’t for others, but, think it’s individual and not a one size fits all

Volume > intensity for marathons Volume, MP work, tempo work, interval work, V.O2 max is the hierarchy

5k is MUCH harder to train for and master than marathon

Unless you crash and burn with severe anemia