I think it's unethical, if you're actively managing your linkedin page and using linkedin to advance your job search, to leave it be. If you were totally not using your page, that potentially would be one thing (one could say it's just outdated), but if you're actually using it, it's unethical to leave it. It's not "technically inaccurate," as you characterize it; it's "inaccurate." And I'm not sure where it would get you, anyway. When you apply to a job, presumably you'd have to send them a resume. Do you plan on continuing this deception on your resume? I think most of us can agree that would be wrong.
If you have indeed learned new skills this year that would be relevant to the technical management position you are seeking, I would work those into your linkedin profile.
But No. 3, or coming up with some stupid title to characterize what you've been doing the past year, is a horrible idea. "Principal medical researcher"? Really? In your current title on Linkedin, you can say something like "technical management professional" and then list your skills, what kind of job you're seeking, in the description.