1st to clarify:
The US govt did not lift a ban on ESC research, it was certainly legal before the new administration. What was done is the US Govt is funding this research now, a research that has little value and can be duplicated with adult stem cells from births, liposuction, and a whole host of other places. Heck one liposuction of me could give more SCs then a billion embryo.
As for your question, it going to be a case by case issue. Some vaccines are derived from aborted babies and still used today with the moral ok to use by the Church since its under a “double effect”. Chemotherapy and radiation therapy were results of the atrocities in WW2, but we are still morally allowed to use them. Where I think the wall will be is if the cure demands continuous death of a embryos, sort of a soylent green situation.