It seems that there is some correlation between cardiovascular risk and blood donation, but this might just be due to a confounding factor: healthy people tend to donate blood more.
E.g. this study [1]:
Despite the significant difference in QRISK2 parameters between study groups, none of these parameters was correlated to the extent of donation when controlling for age, BMI and smoking status.
Or this one [2]:
No significant associations were found between blood donation and the risk of myocardial infarction in analyses restricted to men with hypercholesterolemia or those who never used antioxidant supplements or aspirin. The study results do not support the hypothesis that reduced body iron stores lower CHD risk.
Ironically this other Dutch study [3], shows an association (not causal) between frequent blood donation and cardiovascular health in women but not in men.
[1]: https://pubmed.ncbi.nlm.nih.gov/28797569/ [2]: https://www.ahajournals.org/doi/full/10.1161/01.cir.103.1.52 [3]: https://heart.bmj.com/content/105/16/1260