I think you only think that way because she’s a woman. If a man was doing that he would be seen as a red flag. Like imagine your boyfriend ignoring and not answering your calls for weeks?!. We can only see she insecure as the reader, in reality she’s a terrible partner. Who would want to be with someone who can communicate properly
I don’t really remember the story so I can’t comment on it but responding to your questions I’d talk with my partner and give them a chances to fix the behavior because at the end of the day we are human we’re not perfect but if it doesn’t work I’d leave, and for me these kind of things don’t qualify as “red flags” for me red flags is something when you noticed you need to gtfo immediately but everyone is different so idk + I don’t differentiate between a man and a woman if you suck as person you suck

Guy= green flag
Girl= red flag