Removing co-authors after re-running study 2 years ago, as a PhD student in Department X at a European university, I designed and ran a study and then over the next year wrote it up for submission to decent but not top-level journals. I did 100% of the work, with no useful suggestions from anyne else, and in particular from my PhD advisor, who is also the department head. In fact, the work is quite far afield from his methods, knowledge, and expertise; however, it is understood in local academic culture that the department head goes on the paper, regardless of their contribution (which is typically zero). While preparing the manuscript, we solicited comments from my advisor's colleague, who is a respected researcher on this topic. The comments mostly related to structure, presentation, how to build the story better, etc., but nothing substantial in terms of subject matter. He also said it was a good paper and he wished he were on it. My advisor then "advised" me to put him on the paper. Being a young academic, I didn't know how to say "no", and also thought that maybe it would be strategic to have a more respected name among the co-authors.

Fast-forward to now. I have my PhD and am now an assistant professor in Department Y, no relation to X. The paper has had 1 review from a good journal and 3 desk rejects. To summarize the feedback, they generally say the paper is good and would probably be accepted, were it not for an issue which is considered a methodological flaw in one (but not the other) of the 2 fields which this paper straddles. I am convinced that I should re-run the study to fix this and, if the results stand up, submit it to the remaining relevant journals for which it would be appropriate. My co-authors, when they can even be bothered to respond to my requests for input/opinions on how to proceed, don't want to be bothered with rewriting, etc., and want to just keep trying to push it to the remaining journals.

I am very interested in the idea, I believe it is a good one, and I want to pursue this by rerunning the study without the flaw. Since these co-authors (my former PhD advisor/department head and his colleague) have not given any substantial input or help, it seems justified that they cease to be coauthors when the study is re-run -- it is virtually a new paper at this point. My questions are whether the community would generally agree that this would be wise -- especially since it hurts my job prospects to have papers with big-name researchers, since it's potentially unclear that I'm really the one doing the work. If advisable to eliminate them, I would appreciate any advice about how to navigate this.On the other hand, I do have fears about the potential fallout and am open to keeping them on the paper if necessary, but it's impossible to make progress when they don't respond to my emails about e.g. finalizing design, running/analyzing the experiment, preparing the manuscript, etc. Perhaps it is wiser to keep them, but then how can I make progress with my work without them holding me back?
Just ask them if they’d be okay with you reworking the paper and cutting them out of the author list, or they’d still like to contribute to it.
So your paper has a flaw that you need to rework to get published.  Your coauthors aren’t interested in doing so, so why not just do the polite thing and ask them if they still want to be involved?
If they agree to be cut out of the revised paper, they wouldn’t have any reason to be upset with you for doing so. If they agree to take an active role in revising the paper, they don’t have any reason to be upset, either.