I also did 3 rounds of IVF 12 years ago.
Exogenous hormones have a half life of hours, not years, and will absolutely not still be in your body.
There is no conclusive link between IVF and any type of cancer, however it is biologically plausible for it to increase breast and ovarian risk slightly. If there was any significant signal though this would have become apparent by now as it has been around for many decades.
I have zero fear of taking exogenous hormones, and the doses within menopause hormone therapy are absolutely minuscule compared to what we pumped ourselves with to have our miracles.