This would be fine advice if OP hadn't matched. Unfortunately, OP signed an agreement stating they in good faith intend to attend whatever residency program they match to for a minimum of 45 days after the start date, and anything they do prior to that date to put their good faith in question (e.g. trying to set up a research year, reaching out to other programs about the prospect of joining, etc) would violate that agreement, i.e. a match violation, which may result in a ban from participation in the NRMP in the future.
The by-the-book way of doing this is submitting a specialty change waiver request after those 45 days, then either applying to ERAS after that waiver is approved (which would entail submitting to ERAS after the deadline), or (more feasibly) completing your PGY1 year, then taking a research year or completing your PGY2 year while applying to the match that year (2025). Of course, once you submit that waiver, you program can decide to fire you.
Maybe someone who has actually done this can comment, but I would strongly recommend OP review NRMP policies before making any decisions. My advice remains to complete the residency in which you matched, then reapply.