Are you willing to get the Covid vaccine when offered?

Completely different circumstances, but my wife believes the hormone therapy is related to her breast cancer. She's not a physician and while I think your wife is and know you are, it's worth considering. Her actual doctors have instructed her not to start it again and, yes, she had similar symptoms to those your wife experienced, but not due to the covid vax. They were related in time to the hormones.
Interestingly, a med they can give post menopausal women with breast cancer is Anastrozole, which basically lowers estrogen levels.

So, I could imagine, HR+ early breast cancer risk would increase with estrogen therapy.