I was recently turned down from a role, and given the reason that the other candidate was “already doing this type of work but uses some tools that they’ll bring over” and that this was the only thing that made the distinction.

It for sure hurts to lose out on a job at the last stand. I myself went through a process for an ED position earlier this year and was assured multiple times that nobody cared that I didn't have a PhD in their field because what I was bringing to the table was "far more important" and that I was "definitely the kind of person we want." I went through 7 interviews, flew thousands of miles, sat with every member of the staff and board. And then in the end, they selected the candidate who had none of my experience but a PhD in the field and they said, "Well, but they have a PhD in the field." That nearly broke me. But the way I've tried to look at that situation and that I hope you will also look at yours is that you went through a rather incredible arduous process and got a massive education in how to navigate the long-haul interview that leads to the type of position you really want. So you can sit down and think about the things that went great and the things that made you uncomfortable and the things that made you second guess yourself or them and use that to strengthen your resume, your cover letters, and your interviews. And what I sincerely hope will come of it for you is a much better role than this one you didn't get.