I wonder how the data looks on soccer and the long term effects of headers. It seems any activity that causes the brain to rapidly and repeatedly impact the skull is up for review.
https://www.forbes.com/sites/kimelsesser/2019/11/07/the-conc...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3750422/
Although I bet it would be easier to outlaw headers in soccer (aka football :) than somehow avoid concussions in American/gridiron football.