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Amex has a preapproval site, try it and see what pops up.
Need to see what your real Fico 8's are. Amex uses Experian. If your Experian is 650 and up, probably a pretty good chance to get at least one of the co-branded cards. Check their prequal page along with Discover and Chase.
AAoA, Util, # of Inquries, Scores (EQ,EX,TU), Any negs, # of accounts.
Sorry to hear about the results. Lets see what your data points are and im sure the community can put together a gamplan for you. Worst case you wait out 6 months... don't be bothered by what the system said.