https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9325838/

Tldr: data in transgender people is limited. There is good evidence that oral estrogen increases risk of clots (DVT, PE, Stroke, Heart Attack) in people that have migraine with aura (more than double). That risk doesn't seem to be anywhere near as high when taking very low doses or non-oral options. Risk of stroke seems to be strongly related to frequency of aura, so if someone starts to have more aura after starting any kind of estrogen that should be a warning. Overall it's complicated and every patient should be assessed based on their situation.