Normally in the past FO hiring market your resignation may only have been in issue if you tried to reapply at that same airline. But others would have snatched you up. Unfortunately the hiring market on the FO side has become much more competitive. Not sure if you have been following, but some regionals put a pause on zero Part 121 hour new hire FOs while others have drastically reduced class frequency and size of their classes. With your history it may cause your application to go to the bottom of the pile in the selection process. But then again it never hurts to apply.