There are 2 things people should consider in this debate:
1. If you are opposed to the use of a drug produced using HEK293 cells due to their fetal origin, then you should live by your word and convictions and refuse all modern medicine and biological advances. Virtually all research in labs across the world uses HEK293 and other similar cell lines, and most modern drugs (anti-cancer, etc) use HEK293 either directly or indirectly to manufacture biological drugs
(I make this point because most people who are "very ready" to use this as a reason not to take a vaccine are already biased against vaccines and usually much less willing to apply this standard everywhere logically they should, to be consistent and not be a hypocrite. This to me says more about what they want to believe rather than what they are willing to think through; see point 2).
2. I wonder if you would also refuse or denounce organ transplantation. Let's say specifically, a child on a waiting list for a new heart. A match comes in, another child is a match and has just died. Their parents have consented for their organs to be used in a donation. Do you agree with this? Now, let's say that this child, the donor, was murdered. Is the recipient of the donated organ complicit in that crime by receipt of the donation? Does receiving an organ from someone who was unlawfully killed make you approve of that crime? Does it make you complicit? Are you "remotely cooperating" with that evil?
I contest, that the vast majority of Christians would look at that scenario in point 2 above and say no, the murder was evil but independent and not for the purpose of allowing an organ to be donated to a recipient in need. Very few people I have spoken to about this scenario would call this immoral, for the child in need to receive the transplant.
This is virtually analogous with the issue at hand here. Were HEK293 cells derived from an aborted fetus? Yes, most likely. Was the fetus aborted for the purpose of scientific research? No, not to the best of our knowledge. So if those cells from the aborted fetus are grown on a plastic dish and then used in biological research or in a manufacturing process, why would we consider that cooperation in an evil?