It's very complicated. I just know a lot of research has been going on in this area for about 20 years. From a recent paper:

The observation that female adolescents participating in soccer had a greater risk of documented SRC compared with male adolescents is in line with studies9,20 that have identified sex differences in SRC risk. For example, at the high school level, female soccer athletes have an approximately 60% to 80% greater risk of SRC than male athletes.9,20 Although multiple studies6,8-11 report increased concussion risk in female athletes, reasons for this increased risk remain unclear. In part, this finding might reflect greater likelihood of symptom reporting in female athletes.21

Alternatively, variation in SRC risk between the sexes may be a consequence of physiological differences between male and female athletes contributing to concussion propensity. Female soccer athletes have lower neck strength and girth compared with male athletes,22-25 with these variables inversely associated with linear and rotational head acceleration after soccer ball heading.24,25 At the cellular level, axons in female individuals have smaller and fewer microtubules than those in male individuals, predisposing them to greater risk of injury under dynamic stretch.26 Thus, as a result of anthropometric and brain microstructural differences between the sexes, female athletes may be at greater risk than male athletes of diffuse axonal injury, the principal pathology underlying concussion.3

https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2779117