Inside a ‘photography folder‘ you could use the ‘year > month > day’ auto folder creation option then rename the ‘day’ folders to the name of each race. I do something similar as I rename the day folder with a rough location/subject ie Lake District, Norfolk Seals etc but I do keep the day number so it’s 17 Lake District, 18 Lake District etc if there are multiple days to a trip. So far I have year folders going back to 2012 in one LR catalogue. That seems to work well for me.