You are making a big mistake. I'm reading this as you plan to get a PhD or get clinical experience in nursing, and then somehow turn that into a medical residency. And that you think you'll be taking the USMLE again. None of this will work.
First, the USMLE. There's talk that the USMLE "expires" after 7 years, and that you can take it again. That's not the way it works. You can only take a passed USMLE exam again if you can prove, to the USMLE, that you must in order to get a state license. Just saying "I'm thinking of applying for an XXX state license" won't work, you'll need a letter from the state BoM certifying that you need to take the exam again. And that's only going to happen if you meet all the other requirements for licensure, which you won't since you don't have any GME experience. So, bottom line, you are not taking the USMLE again.
A PhD will not make you a more competitive residency candidate. As already mentioned, you'll be more years from your graduation, more distant from your clinical work. Big research programs are not going to consider you, and smaller community programs won't care about your research, or might even be put off by it.
Getting clinical experience as an RN is also a dead end. Nursing experience does not equal physician experience, and if you try to "act like a physician" while being a nurse you'll be fired immediately. In fact, some employers may specifically avoid hiring you because of your medical training -- there would be concern that you would be held to a physician standard rather than a nurse standard. Residency programs will not see this as clinical work.
So, if you want to get a PhD and be a researcher - totally fine plan. If you want to be a nurse, probably a workable plan but your prior medical training may be an issue and this is not a path to being a physician. If you plan to be an ARNP, that also runs into the problem of your medical training but might be possible.