I'm going to flirt with and sext a bunch of girls
Why would you sext and flirt with these girls?
To improve my chances of getting a girl
I see your point, but it's wrong to talk to girls just for sex. You should only be messaging one girl at a time.
Ok, I'm going to stop if girls don't want to talk to me.
It's good that you are willing to consider their feelings.  It's okay to flirt with girls if they seem to be interested in you, but if not, you shouldn't treat them as objects.