Level down offer, should I consider this?

I am currently Associate Director at Vertex and have been offered Senior Manager J&J (after applying for Director position). The feedback is that I don't have line management experience, which seems to be must for Director position at J&J. They are saying Senior Manager is equivalent to AD. And I will have direct reports with this role, but report into Director. Sounds more like lateral move to get line management experience. I haven't gone into pay, RSU's, etc. Hiring manager sounds confident that can work. Should I go ahead with next steps? To add more context, J&J position will be local for me and commutable. I am remote with Vertex. All positions at Vertex are Boston based. For any growth at Vertex, I need to relocate to Boston. I am afraid this line manager point will always come up at big pharma in New Jersey. Small biotechs are no longer a safe place with all the M&A. I am in IT Business Partner sort of role and this gets easily chopped off in a M&A. I have also been at AD level for 4 years now. Making a lateral move looks like a step back. I am confused!! Any suggestions?