You need to be at a peak for the day. It is not necessarily the best athlete who wins, it is the best prepared 2. Choose the event that best suits you internationally.
Basic speed is the governing factor.
The aim is to develop sufficient endurance to maintain the necessary speed over the race distance to be successful. In middle distance and distance events, a high aerobic threshold is necessary. Stamina can be continually developed. Aerobic development is a limited factor. Once anaerobic training is started, it must be continued, otherwise development is lost.