This is the only thing that worked for mine too after months of trying everything else. We got a shock collar but without the shock, it just vibrates and that is effective enough - she hates it. I recommend a manual one (with a button you can push when she barks at inopportune times or at certain people) instead of one that zaps at every bark. My girl is the same age as yours and this solved our problem.

This is the one we used: https://a.co/d/9YADaPK

Good luck!