Matters of health are probably the wrong ones to speculate on or try to speak authoritatively about when you "didn't spend much time researching" them. CTE can be a problem in soccer specifically because "Evidence indicates that repetitive concussive and subconcussive blows to the head cause CTE"[emphasis mine][1]. You don't need to be "dazed or knocked out" to cause damage. Suggesting otherwise is dangerous.

[1] - https://en.wikipedia.org/wiki/Chronic_traumatic_encephalopat...