I’m working on my new WP site on a staging site. What’s the most efficient way to transfer my old WP blog posts to the new site?

I have about 100 blogs on my current site. Working on a staging site. Wondering if anyone can recommend a good / efficient solution for moving all the blogs over. I can of course just copy and paste them, but that'd be quite time intensive. Not sure the best way to go about it, but I presumed someone here might be able to give a good recommendation.

Thank you in advance!